Natyashastra
षट्संख्यं सप्तसंख्यं च ललितैः पादविक्रमैः । अधिकुर्यादपक्रान्तमतिक्रान्तं च वामकम् ॥ ३०॥
Using six and seven sequential graceful foot movements, one should execute the Apakrānta and Atikrānta on the left side.
english translation
SaTsaMkhyaM saptasaMkhyaM ca lalitaiH pAdavikramaiH । adhikuryAdapakrAntamatikrAntaM ca vAmakam ॥ 30॥
hk transliteration by Sanscript