72 Pa. Stat. § 8705-B
The provisions of section 41 of the Internal Revenue Code and the regulations promulgated regarding those provisions shall apply to the department's interpretation and administration of the credit provided by this article. References to the Internal Revenue Code shall mean the sections of the Internal Revenue Code as existing on any date of interpretation of this article. However, if those sections of the Internal Revenue Code referenced in this article are repealed or terminated, references to the Internal Revenue Code shall mean those sections last having full force and effect. If after repeal or termination the Internal Revenue Code sections are revised or reenacted, references herein to Internal Revenue Code sections shall mean those revised or reenacted sections.
72 P.S. § 8705-B