Surya Siddhanta
ग्रहात् प्राग्भगणार्धस्थः प्राङ्मुखम् कर्षति ग्रहम् । उच्चसम्ज्ञो +अपरार्धस्थस् तद्वत् पश्चान्मुखम् ग्रहम्॥
The Deity called Uchcha (apogee) draws the planet to the east or west (from its uniform progress) according as the Deity is east or west of the planet at a distance less than six signs.
english translation
grahAt prAgbhagaNArdhasthaH prAGmukham karSati graham । uccasamjJo +aparArdhasthas tadvat pazcAnmukham graham॥
hk transliteration by Sanscript