Librestream Technologies, Inc.v.John A. ThomasonDownload PDFPatent Trial and Appeal BoardJan 5, 201510054404 (P.T.A.B. Jan. 5, 2015) Copy Citation Trials@uspto.gov Paper 17 571-272-7822 Entered: January 5, 2014 UNITED STATES PATENT AND TRADEMARK OFFICE ____________ BEFORE THE PATENT TRIAL AND APPEAL BOARD ____________ LIBRESTREAM TECHNOLOGIES, INC., Petitioner, v. JOHN A. THOMASON 1 , Patent Owner. ____________ Case IPR2014-00368 Patent 6,690,273 B2 Before KRISTEN L. DROESCH, MICHAEL W. KIM, and GREGG I. ANDERSON, Administrative Patent Judges. DROESCH, Administrative Patent Judge. FINAL WRITTEN DECISION 35 U.S.C. § 318 and 37 C.F.R. § 42.73 1 Wireless Remote System LLC assigned all of its rights, title, and interest in U.S. Patent No 6,690, 273 B2 to John A. Thomason, effective October 1, 2014. Paper 16. IPR2014-00368 Patent 6,690,273 B2 2 I. INTRODUCTION Librestream Technologies Inc., (“Petitioner”) filed a Petition (Paper 1, “Pet.”) on January 21, 2014 requesting inter partes review of claims 1 and 2 (“the challenged claims”) of U.S. Patent No. 6,690,273 B2 (“the ’273 Patent”). See 35 U.S.C. §§ 311-319. Wireless Remote System LLC (Patent Owner prior to October 1, 2014) did not file a Preliminary Response to the Petition. We instituted inter partes review of claims 1 and 2 on June 12, 2014. Paper 5. Following institution of trial, the parties indicated that they had engaged in settlement negotiations, but that a settlement did not result. See Papers 12, 13. Patent Owner’s counsel indicated to the Board that the Patent Owner would not be able to file a Patent Owner Response by the Due Date of September 24, 2014 (this Due Date was extended by stipulation between the parties from its original Due Date of August 27, 2014). Paper 12. After providing Patent Owner one last opportunity to file a Patent Owner Response by October 3, 2014, counsel for Wireless Remote System LLC affirmatively notified the Board that no Patent Owner’s Response would be filed. Papers 13, 14. The Due Date for filing a Patent Owner Response tolled on October 3, 2014. After holding a conference call on October 9, 2014 with counsel for Petitioner and counsel for Wireless Remote System LLC to confirm that it was indeed Patent Owner’s intent to forego the filing of a Patent Owner’s Response and with the express consent of all counsel, we issued an Order vacating Due Dates 2 through 7 of the Scheduling Order, thereby enabling trial to proceed to a final written decision without further input from the parties. Paper 15. The Board did not receive any further communication concerning this issue from either party. IPR2014-00368 Patent 6,690,273 B2 3 We have jurisdiction under 35 U.S.C. § 6(c). In this final written decision, issued pursuant to 35 U.S.C. § 318(a) and 37 C.F.R. § 42.73, we determine Petitioner has shown by a preponderance of the evidence that all of the challenged claims of the ’273 Patent are unpatentable. A. Related Proceedings Petitioner indicates the ’273 Patent is at issue in Wireless Remote System LLC v. Librestream Technologies, Inc., No 6:12-cv-00899 (E.D. Tex.). Pet. 1. There is also an instituted inter partes review of claims 1–13 of related U.S. Patent No. 6,317,039 B1 (IPR 2014-00369), which was also filed by Petitioner. Id.; IPR 2014-00369, Paper 6 (June 12, 2014). B. The ’273 Patent (Ex. 1001) The ’273 Patent relates to “[a] method and system for remote assistance and review of a technician or multiple technicians, in real time, working with equipment of various complexit[ies].” Ex. 1001, Abs; col. 1, ll. 56–60. Figure 1 of the ’273 Patent is reproduced below: Figure 1 depicts a block diagram of a wireless remote system. Ex. 1001, col. 2, ll. 46–47, col. 3, ll. 7–8. Remote system 101, utilized by mobile field IPR2014-00368 Patent 6,690,273 B2 4 technician 102, is coupled by wireless network 106 to local station 108, utilized by local master technician 109. Id. at col. 3, ll. 9–14. Remote system 101 includes wireless portable processor 103, wireless audio headphone/microphone 104, and wireless camera 105. Id. at col. 3, ll. 9–12; see id. at col. 3, ll. 57–60. Wireless portable processor 103 further includes an embedded web browser that connects to Internet 107 via wireless network 106. Id. at col. 3, l. 60–col. 4, l. 8. Local station 108 includes local processor 110 and audio/microphone headset 111. Id. at col. 3, ll. 16–18; see id. at col. 5, ll. 51–54, 60–63. The ’273 Patent describes another embodiment in which a centralized expertise station including one or more local processors 110 is coupled to multiple wireless portable remote systems 102. Id. at col. 2, ll. 55–57; col. 7, ll. 43–47; Fig. 5. Mobile field technician 102 may operate/service/maintain an apparatus at a remote job site with the advice and control of local master technician 109. Ex. 1001, col. 3, ll. 19–22. Local master technician 109 may view and hear the same stimuli as remote field technician 102, at the remote site, by way of audio and video sensors at the remote site (e.g., microphone 104, camera 105). Id. at col. 3, ll. 23–26; see id. at col. 5, l. 67– col. 6, l. 3. Remote field technician 102 communicates with local master technician 109 by way of wireless network 106 or Internet 107, or both. Id. at col. 3, ll. 27–29. C. Illustrative Claim Claims 1 and 2 are independent claims. Claim 1, reproduced below, is illustrative of the claims at issue. 1. A method for providing assistance to a plurality of mobile field operators by a local master technician, comprising the steps of: IPR2014-00368 Patent 6,690,273 B2 5 operating a plurality of wireless remote systems wherein a wireless remote system is operated by each mobile field operator, said wireless remote system comprising an audio sensor, a video sensor, a wireless portable processor, an audio receiver and a wireless transceiver, wherein operating the wireless remote system comprises moving the audio sensor, the video sensor, the audio receiver and wireless transceiver with the mobile field operator; operating a local station by a local master technician, said local station comprising an audio sensor, a video receiver, a processor and an audio receiver; communicating over a wireless network between said local station and said plurality of wireless remote systems; delivering remote sound from the audio sensor of each wireless remote system of said plurality to said local station audio receiver; delivering remote images from the video sensor of each wireless remote system of said plurality to said local station monitor; delivering local sound from said local station audio sensor to the receiver of each wireless remote system of the plurality; viewing and hearing by said local master technician of stimuli available to each mobile field operator of said plurality; communicating between said local master technician and each mobile field operator of the plurality; and, directly advising each mobile field operator of the plurality by said local master technician. II. ANALYSIS A. Principles of Law To prevail on its challenges to the patentability of the claims, Petitioner must prove unpatentability by a preponderance of the evidence. 35 U.S.C. § 316(e); 37 C.F.R. § 42.1(d). A claim is unpatentable under IPR2014-00368 Patent 6,690,273 B2 6 35 U.S.C. § 103(a) if the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art to which said subject matter pertains. KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 406 (2007). For an obviousness analysis, it can be important to identify a reason that would have prompted one with ordinary skill in the art to combine prior art elements in way claimed by the patent at issue. Id. at 418 (quoting In re Khan, 441 F.3d 977, 988 (Fed. Cir. 2006)). We analyze the instituted grounds of unpatentability in accordance with these principles. B. Grounds of Unpatentability We instituted inter partes review of the following specific challenged claims as unpatentable under 35 U.S.C. § 103 based on the following prior art references (Pet. 3): Claim References 2 1 Beller and Ziegra 2 Beller, Ziegra, McPheely, Thorpe, and David 1. Obviousness of Claim 1 Over Beller and Ziegra With respect to the assertion of unpatentability of claim 1, we have reviewed the Petition, as well as the evidence discussed in the Petition. We are persuaded by a preponderance of the evidence that claim 1 is 2 The Petition relies on the following references: U.S. Patent No. 6,046,712 A (Ex. 1008) (“Beller”); U.S. Patent No. 5,619,183 (Ex. 1004) (“Ziegra”); U.S. Patent No. 5,844,601 (Ex. 1006) (“McPheely”); Thorpe et al., Multimedia communications in construction, 108 PROCEEDINGS OF THE ICE - CIVIL ENGINEERING 12–16 (February 1995), (Ex. 1005) (“Thorpe”); and U.S. Patent No. 5,544,649 (Ex. 1016) (“David”). The Petition also relies on the Declaration of Anthony Mines (Ex. 1010). IPR2014-00368 Patent 6,690,273 B2 7 unpatentable under 35 U.S.C. § 103 as obvious over Beller and Ziegra. See Pet. 3, 8–25. a. Beller (Ex. 1008) Beller describes a head-mounted system for providing “interactive visual and audio communications between a user of the head mounted system and an operator of a remote system.” Ex. 1008, Abs. The operator of the system can see what the user of the head-mounted system is viewing, and the user of the head-mounted system can view inputs received from the remote system. Id. at col. 1, ll. 50–57. Figure 1 of Beller is reproduced below: Figure 1 depicts head-mounted communication system 10 in communication with remote assistant’s terminal 13. Ex. 1008, col. 3, ll. 17–19, 42–45. IPR2014-00368 Patent 6,690,273 B2 8 Figure 3 of Beller is reproduced below: Figure 3 depicts the controls of head-mounted communication system 10 and remote assistant’s terminal 13. Ex. 1008, col. 3, ll. 23–25. Head- mounted communication system 10 includes housing 50, RF communication system 96, camera 15, earphone 27, microphone 29, and display 14. Id. at col. 3, ll. 45–48; col. 4, ll. 18–21, 39–51; col. 4, l. 66–col. 5, l. 4; col. 7, ll. 39–43. Remote assistant’s terminal 13 includes display/touch panel 19, keyboard 21, microphone 112, speaker/earphone 116, and radio frequency communication system 104. Id. at col. 3, l. 52–col. 4, l. 5; col. 7, ll. 49–66. Head-mounted system 10 and remote terminal 13 communicate via radio frequency network 200, which includes a plurality of base stations 202, 203. Id. at col. 7, ll. 21–25. Beller teaches that when a radio system is employed to provide wireless communication with remote terminal 13, radio system 96 of head- mounted system 10 formats audio and video data into packets. Ex. 1008, IPR2014-00368 Patent 6,690,273 B2 9 col. 7, ll. 1–3. Each packet includes a header portion that includes an address or code identifying the particular terminal 13 to which the signal is intended to be sent, as well as an address or code identifying the particular head-mounted communication system 10 that is transmitting the signal. Id. at col. 7, ll. 3–12. Upon receipt of a radio frequency signal, radio system 96 of head-mounted system 10 compares the destination identity code contained within the header portion of the received signal to the unit’s own identity code stored in memory, to determine if there is a match. Id. at col. 8, ll. 12– 17. If there is a match, radio system 96 determines whether the received signal was intended for the particular head-mounted system, and the system couples the received audio and video data to controller 88 of head-mounted system 10. Id. at col. 8, ll. 16–19. Controller 88 controls the display to depict the retrieved video data, and further controls an audio output interface and speaker to generate audio from the retrieved audio data. Id. at col. 3, 21–24. b. Ziegra (Ex. 1004) Ziegra describes a method and system for remote assistance and review of an operator working on complex equipment. Ex. 1004, Abs, col. 1, ll. 52–54; see id. at Fig. 1. An operator at a local site is coupled to an advisor at a station at a remote site, so that the advisor may view and hear the same stimuli as the operator, and may communicate with the operator. Id. at Abs.; col. 1, ll. 54–62. The operator has limited training, or is otherwise in need of support, and may be a field engineer or technician. Id. at Abs.; col. 2, ll. 11–13. The local station comprises a video and audio sensor, and a receiver for a communication link with the remote station. Id. at col. 1, l. 65–col. 2, l. 3. The remote station comprises a video and audio IPR2014-00368 Patent 6,690,273 B2 10 display, and a transmitter for the communication link with the remote station. Id. at col. 2, ll. 6–10. The advisor views and listens to the local apparatus, and gives advice to the operator for manipulating the local apparatus. Id. at Abs.; col. 2, ll. 27–33. The operator operates the local apparatus as if the advisor were peeking over the operator’s shoulder. Id. at Abs.; col. 2, ll. 34–35. c. Claim 1 We are persuaded that Petitioner has shown by a preponderance of the evidence that claim 1 is unpatentable in view of Beller and Ziegra. For example, we are persuaded that Petitioner relies properly on Beller and Ziegra to teach “[a] method for providing assistance to a plurality of mobile field operators by a local master technician,” based on the following: (1) Beller contemplates multiple terminals 13 operated by respective local master technicians advising multiple field operators (users), based on Beller’s disclosure that each head-mounted system 10 has an identity code that determines whether signals sent over radio system 96 are intended for that particular head-mounted system (Pet. 9–10 (citing Ex. 1010 ¶ 42a; Ex. 1008, col. 8, ll. 12–18)); and (2) Ziegra teaches a plurality of local stations each with its own local processor that communicates with the remote station (Pet. 10 (citing Ex. 1010 ¶ 42b; Ex. 1004, col. 6, ll. 37–41); see Pet. 22. Petitioner provides the following articulated reasoning to explain why one with ordinary skill in the art at the time of the invention would have combined the teachings of Beller and Ziegra: even if Beller [does] not inherently teach providing assistance to more than one field operator, it would have been obvious to . . . modify Beller to use multiple head mounted systems to advise multiple field operators because Ziegra teaches that IPR2014-00368 Patent 6,690,273 B2 11 providing plural remote systems is a “preferred” implementation of a system for providing remote assistance. Id. at 10 (citing Ex. 1004, col. 6, ll. 37–41; Ex. 1010 ¶ 42b). Petitioner further asserts that there are no unexpected results from the duplication of Beller’s basic system because it simply allows more users and master technicians to communicate with one another. Id. at 10–11 (citations omitted). We are persuaded Petitioner’s proffered rationale and evidence is sufficient to support the proposed modification. Petitioner relies on Beller’s microphone 29, camera system 15, microprocessor 88, earphone 27, and radio transceiver 98 of Beller’s head- mounted communication system 10, as modified to use multiple head- mounted systems 10, to teach “operating a plurality of wireless remote systems . . . operated by each mobile field operator, said wireless remote system comprising an audio sensor, a video sensor, a wireless portable processor, an audio receiver and a wireless transceiver,” as recited in claim 1. Pet. 11–13 (citing Ex. 1008, col. 1, ll. 33-40, 64; col. 2, ll. 2–5; col. 3, ll. 45–48; col. 4, l. 66–col. 5, l. 2; col. 6, ll. 59–61; col. 7, ll. 39–43; col. 10, ll. 36–43; Ex. 1010 ¶¶ 43–48); see id. at 22–23. Petitioner further asserts that Beller’s description that components of head-mounted communications system 10 can be body-worn or hand-held teaches “moving the audio sensor, the video sensor, the audio receiver and wireless transceiver with the mobile field operator,” as recited in claim 1. Id. at 13–14 (citing Ex. 1008, col. 1, ll. 62–64; col. 6, ll. 10–12; col. 11, ll. 34–37; Fig. 1; Ex. 1010 ¶ 49); see Pet. 23. Petitioner further relies on microphone 112 and audio input interface 114, display 19, which displays received video information, processor 110, and speaker/earphone 116 of Beller’s remote assistant’s terminal 13 for teaching “operating a local station by a local master technician, said local IPR2014-00368 Patent 6,690,273 B2 12 station comprising an audio sensor, a video receiver, a processor and an audio receiver,” as recited in claim 1. Id. at 14–16 (citing Ex. 1008, col. 1, ll. 32–45; col. 3, ll. 52–57; col. 7, ll. 52–59; Figs. 1–3; Ex. 1010 ¶¶ 50–54), see Pet. 23. Petitioner contends that Beller’s radio frequency network 200, camera system 15, which picks up images within at least a portion of the field of view of user of system 10, and transmits the images to remote assistant’s terminal 13, and microphone 29, which receives audio and transmits audio to speaker/earphone 116 of remote terminal 13, as modified to use multiple head mounted systems 10, teaches communicating over a wireless network between said local station and said plurality of wireless remote systems; delivering remote sound from the audio sensor of each wireless remote system of said plurality to said local station audio receiver; delivering remote images from the video sensor of each wireless remote system of said plurality to said local station monitor; delivering local sound from said local station audio sensor to the receiver of each wireless remote system of the plurality[,] as recited in claim 1. Pet. 16–18 (citing Ex. 1008, col. 3, ll. 5–10, 45–57; col. 4, l. 66–col. 5, l. 2; col. 7, ll. 21–22, 56–59; col. 10, ll. 44–46; col. 11, ll. 14–20; Fig. 6; Ex. 1010 ¶¶ 55–60); see Pet. 23–24. For the limitation “viewing and hearing by said local master technician of stimuli available to each mobile field operator of said plurality,” Petitioner asserts Beller discloses that operator of terminal 13 can see at least a portion of the field of view of the user or head mounted system picked up by camera 15. Pet. 19 (citing Ex. 1008, col. 3, ll. 52–57; Ex. 1010 ¶ 61a); see Pet. 25. Petitioner acknowledges that Beller does not disclose expressly that microphone 29 permits the local master technician at terminal IPR2014-00368 Patent 6,690,273 B2 13 13 to hear the stimuli available to the user of head mounted system 10. Id. at 19 (citing Ex. 1008, col. 4, l. 66–col. 5, l. 2). Petitioner relies on Ziegra for teaching an operator at a local station is coupled to a remote advisor station, so that the advisor may view and hear the same stimuli as the operator. Id. at 19–20 (quoting Ex. 1004, Abs.); see Pet. 25. Petitioner provides the following articulated reasoning explaining why one with ordinary skill in the art at the time of the invention would have modified the teachings of Beller in light of Ziegra’s teachings: it would have been obvious to . . . use the microphone and camera of Beller’s head mounted system 10 to provide the local master technician . . . with the stimuli available to the user of [] head mounted system 10 because it would permit the local master technician to view and listen to an apparatus that the user was operating, maintaining, or repairing[,] and thereby permit the local master technician to give the user better advice. Id. at 20 (citing Ex. 1004, Abs.; Ex. 1010 ¶ 61c). We are persuaded that Petitioner’s proffered rationale and evidence is sufficient to support the proposed modification. Last, Petitioner asserts that Beller’s speaker 112 and microphone 116 at terminal 13, and wireless two-way communication between head-mounted system 10 and remote terminal 13, that permit the user to gain assistance from a supervisor located remotely from the repair site, and Beller’s contemplation of a supervisor giving instructions, as modified to use multiple local stations, further teaches “communicating between said local master technician and each mobile field operator of the plurality; and, directly advising each mobile field operator of the plurality by said local master technician,” as recited in claim 1. Pet. 20–21 (citing Ex. 1008, col. 1, ll. 34–37, 43–45; col. 2, ll. 2–5; Ex. 1010 ¶¶ 62–63); see Pet. 25 (also citing Ex. 1004, col. 6, ll. 38–43). IPR2014-00368 Patent 6,690,273 B2 14 After considering Petitioner’s position and evidence proffered in support of its position, we determine that Petitioner has shown by a preponderance of the evidence that claim 1 is unpatentable under 35 U.S.C. § 103(a) as obvious over Beller and Ziegra. 2. Obviousness of Claim 2 Over Beller, Ziegra, McPheely, Thorpe, and David Regarding the assertion of unpatentability of claim 2, we have reviewed the Petition, as well as the evidence discussed in the Petition. We are persuaded by a preponderance of the evidence that claim 2 is unpatentable under 35 U.S.C. § 103 as obvious over Beller, Ziegra, McPheely, Thorpe, and David. See Pet. 3, 26–38. a. David (Ex. 1016) David describes an ambulatory (in the home) patient health monitoring system in which a patient at a remote station is monitored by a health care worker at a central station. Ex. 1016, Abs; col. 4, ll. 57–61, 66–67. Cameras are provided at the patient’s remote location and at the central station to enable interactive visual and audio communication between the patient and the health care worker. Id. at Abs.; col. 5, ll. 26–29, 54–59. David provides the following additional disclosure: [i]f a staff or team of patient monitors or health care workers at the central station are employed, as when a large number of patients are being monitored, multiple cameras or even small- scale studios may be used, one for each health monitor or nurse, so that individual patients at the remote locations can see their own particular health care worker that they are used to. Id. at col. 11, ll. 22–28. IPR2014-00368 Patent 6,690,273 B2 15 b. Claim 2 Independent claim 2 recites similar limitations as claim 1. However, claim 2 recites “a plurality of local master technicians,” and “the plurality of master technicians” instead of “a local master technician,” and “said local master technician,” as recited in claim 1. Pet. 28; compare claim 1 (Ex. 1001, col. 9, l. 48–col. 10, l. 21), with claim 2 (Ex. 1001, col. 10, ll. 22–60). We are persuaded that Petitioner relies properly on their analysis of Beller as modified by Ziegra with respect to claim 1 to address all of the limitations of claim 1, with the exception of the “plurality of local master technicians.” Pet. 26, 33–38; see id. at 8–25. Petitioner asserts that Beller contemplates multiple terminals 13 operated by respective local master technicians advising multiple field operators, because Beller discloses each terminal 13 has an address or code identifying the particular terminal 13 and head-mounted system 10 use the address or code of the particular terminal for which a signal is intended. Id. at 28–29 (citing Ex. 1010 ¶¶ 73–74; citing Ex. 1008, col. 7, ll. 8–12). Petitioner further asserts that “[u]sing more than one terminal at the claimed local station would have also been a matter of convenience and would be more cost-effective than, for example, dedicating a separate service center to each individual terminal 13 of Beller’s system.” Id. at 29 citing (Ex. 1010 ¶ 75). Petitioner also asserts that there are no unexpected results from the duplication of Beller’s basic system because it simply allows more users and master technicians to communicate. Id. at 29– 30 (citing Ex 1010 ¶¶ 76, 77). We are persuaded that the Petitioner has provided sufficient analysis and evidence to support its conclusion. Also addressing the “plurality of master local technicians,” Petitioner asserts that David teaches an interactive conferencing system by which a IPR2014-00368 Patent 6,690,273 B2 16 remote health care worker provides instructions to an ambulatory patient, and contemplates multiple conferencing systems so that a team of health care workers can remotely provide advice to multiple patients. Id. at 31 (citing Ex. 1016, Abs., col. 6, ll. 31–51; col. 11, ll. 21–28). Petitioner contends it would have been obvious to one with ordinary skill in the art at the time of the invention to modify Beller to use Beller’s system with multiple local master technicians (i.e., assistants or supervisors) operating multiple terminals [] for [the following] reasons: . . . [1] David expressly teaches that each of the remote experts (i.e., health care workers) can have their own studios so that each patient can interact with and see their own particular health care worker, and Thorpe and Ziegra teach that the remote expert systems have application in both the construction industry and medical fields, and [2] it would have been apparent to one of ordinary skill in the art . . . that this modification to Beller would predictably and advantageously permit multiple supervisors to communicate with multiple users, each with their own head mounted system 10, and thereby permit more than two users to be advised simultaneously by different supervisors. Id. at 32 (citing Ex. 1010 ¶ 81). We are persuaded Petitioner’s proffered rationale and evidence is sufficient to support the proposed modification. Petitioner further asserts that McPheely and Thorpe also teach the above limitation. Id. at 30–31. Upon consideration of Petitioner’s position and evidence proffered in support of its position, we determine that Petitioner has shown by a preponderance of the evidence that independent claim 2 is unpatentable under 35 U.S.C. § 103 as obvious over Beller, Ziegra, McPheely, Thorpe, and David. IPR2014-00368 Patent 6,690,273 B2 17 III. CONCLUSION Based on the record before us, Petitioner has demonstrated by a preponderance of the evidence that claims 1 and 2 are unpatentable. IV. ORDER Accordingly, it is: ORDERED that Petitioner has demonstrated by a preponderance of the evidence that claims 1 and 2 of U.S. Patent No. 6,690,273 B2 are unpatentable; and FURTHER ORDERED that because this is a final decision, parties to the proceeding seeking judicial review of the decision must comply with the notice and service requirements of 37 C.F.R. § 90.2. IPR2014-00368 Patent 6,690,273 B2 18 PETITIONER: Robert C. Mattson Vincent K. Shier Oblon Spivak cpdocketMattson@oblon.com cpdocketshier@oblon.com PATENT OWNER: David S. Moreland Lawrence A. Aaronson Meunier Carlin & Curfman dmoreland@mcciplaw.com laaronson@mcciplaw.com John A. Thomason j.thomason@metroenv.com Copy with citationCopy as parenthetical citation