Natyashastra
सव्यस्य पृष्ठतो वामश्चरणस्तु यदा भवेत् । तस्यापसर्पणं चैव ज्ञेया साध्यर्धिका बुधैः ॥ १७॥
Adhyardhikā—the left foot on the back (i.e. heel) of the right one, the latter to be drawn away ॥ a Tāla and half a part॥.
english translation
savyasya pRSThato vAmazcaraNastu yadA bhavet । tasyApasarpaNaM caiva jJeyA sAdhyardhikA budhaiH ॥ 17॥
hk transliteration by Sanscript