68 Pa. C.S. § 4204
A description of a unit which sets forth the name of the cooperative, the recording data for the declaration, the county or counties in which the cooperative is located and the identifying number of the unit is a legally sufficient description of that unit and all rights, obligations and interests appurtenant to that unit which were created by the declaration or bylaws. Proprietary leases and memoranda or short forms thereof as well as all instruments of transfer of cooperative interests and all instruments creating security interests in cooperative interests may be recorded in the same records as are maintained by the recorder for the recording of like instruments and, if recorded, shall be indexed by the recorder in the same manner as like instruments are recorded.
68 Pa.C.S. § 4204