Shiva Purana
ब्रह्महत्यादिपापानां निष्कृतिं कर्तुमुद्यतः । मासमात्रं संहितां तां पठित्वा मुच्यते ततः ४२ ।
The person intending to perform expiatory rites for the sins of Brahma-hatyā etc. should read that Saṃhitā for a month. He shall be freed of that sin.
english translation
brahmahatyAdipApAnAM niSkRtiM kartumudyataH । mAsamAtraM saMhitAM tAM paThitvA mucyate tataH 42 ।
hk transliteration by Sanscript