Shiva Purana
अकारमप्युकारं च मकारं बिन्दुसंयुतम् ॥ नमोन्तं प्रोच्य सर्वत्र हृदयादौ न्यसेदथ ॥ ६५ ॥
Everywhere “A”, “U”, “M” with the Bindu, and the mantra ending with Namaḥ shall be uttered and the Nyāsa of the hand in the heart etc. be performed.
english translation
akAramapyukAraM ca makAraM bindusaMyutam ॥ namontaM procya sarvatra hRdayAdau nyasedatha ॥ 65 ॥
hk transliteration by Sanscript