101 Pa. Code § 13.62
Every transcribed copy of a bill is checked against the manuscript from which it was copied. Original bills are read by one person for misspelled words, transposed lines and errors in language. Amendatory bills and bills containing repeals or other references to or quotations from existing law are proofread by two persons against the language in the Laws of Pennsylvania. In addition, all references to existing law are carefully checked as to date, page in the Laws of Pennsylvania and act number and as to whether there are intervening amendments, repeals or other circumstances affecting the language or status of the provision referred to or amended. For this purpose, the marked copies of the Laws of Pennsylvania are used.
101 Pa. Code § 13.62