Brihat Parashara Hora Shastra
फलाभावं विजानीयात् समे सूर्यनभश्चरे। मध्येऽनुपातात् सर्वत्र ह्युदयास्तविंशोपकाः॥ २९॥
One with an identical longitude in comparison to Sūrya‟s will destroy the good effects. Rule of three process be applied to the Grah in between these positions.
english translation
phalAbhAvaM vijAnIyAt same sUryanabhazcare। madhye'nupAtAt sarvatra hyudayAstaviMzopakAH॥ 29॥
hk transliteration by Sanscript