Shiva Purana
तत्रादौ शिवयोः ॥ पार्श्वे दक्षिणे वामतः क्रमात् ॥ गंधाद्यैरर्चयेत्पूर्वं देवौ हेरंबषण्मुखौ ॥ १ ॥
Upamanyu said:— 1. There at the outset he shall worship lords Heramba and Ṣaṇmukha on either side, the right and the left in order, of Śiva and Śivā.
english translation
tatrAdau zivayoH ॥ pArzve dakSiNe vAmataH kramAt ॥ gaMdhAdyairarcayetpUrvaM devau heraMbaSaNmukhau ॥ 1 ॥
hk transliteration by Sanscript