Shiva Purana
इति स्तुत्वा महादेवं प्रणवात्मानमव्ययम्॥ दत्त्वा पराङ्मुखाद्यञ्च पश्चादीशानमस्तके॥ २३॥
Thus praising the inexhaustible Mahadeva, the oṁkāra-self. Giving the other face and the rear to the north on the head.
english translation
iti stutvA mahAdevaM praNavAtmAnamavyayam॥ dattvA parAGmukhAdyaJca pazcAdIzAnamastake॥ 23॥
hk transliteration by Sanscript