Natyashastra
यत्र तत्रापि संयोज्यमाचार्यैर्नाट्यशक्तिनः । प्रायेण करणे कार्यो वामो वक्षःस्थितः करः ॥ ५७॥
Wherever required, experts in dramatic art should skillfully apply these movements. In general, during a Karaṇa, the left hand should be positioned on the chest.
english translation
yatra tatrApi saMyojyamAcAryairnATyazaktinaH । prAyeNa karaNe kAryo vAmo vakSaHsthitaH karaH ॥ 57॥
hk transliteration by Sanscript