Shiva Purana
ॐमित्यथ समुद्धृत्य स्वस्तिवाचनपूर्वकम् ॥ गर्ते योगासने स्थाप्य प्राङ्मुखं स्याद्यथा तथा ॥ ५५ ॥
Then he lifted up the mantra 'Om' and said Swastika. Place the yoga seat in the pit and face east in the same way.
english translation
OMmityatha samuddhRtya svastivAcanapUrvakam ॥ garte yogAsane sthApya prAGmukhaM syAdyathA tathA ॥ 55 ॥
hk transliteration by Sanscript