Shiva Purana
पयः पृथिव्यामिति च पयसा स्नानमाचरेत् । दधिक्राव्णेतिमंत्रेण दधिस्नानं च कारयेत् 1-20-२० ।
The ceremonial ablution with milk shall be performed with the mantra “Payaḥ Pṛthivyām”॥ 18॥ etc. The ceremonial ablution with curd shall be performed with the mantra “Dadhi Krāvṇaḥ॥ 19॥” etc.
english translation
payaH pRthivyAmiti ca payasA snAnamAcaret । dadhikrAvNetimaMtreNa dadhisnAnaM ca kArayet 1-20-20 ।
hk transliteration by Sanscript