Surya Siddhanta
ऊना चेत् स्यात् तदा भावी वामम् युग्मपदस्य च । पदान्यत्वम् विधोः क्रान्तिविक्षेपाच् चेद् विशुध्यति॥
If less, it is still to come : in an even quadrant, the contrary is the case. If the moon's declination is to be subtracted from her latitude, the rules as to the quadrant are to be reversed.
english translation