Brihat Parashara Hora Shastra
त्रिकोणात् स्वात्सुखस्वाऽन्त्यधीधर्मायुःस्वतुङ्गपाः। सुहृदो रिपवश्वान्वे समाश्चोभयलक्षणाः॥ ५५॥
Natural Relationships. Note the Rāśis, which are the 2nd, 4th, 5th, 8th, 9th and 12th from the Mooltrikon of a Grah. The Grahas ruling such Rāśis are its friends, apart from the Lord of its exaltation Rāśi. Lords other than these are its enemies. If a Grah becomes its friend as well, as its enemy (on account of the said two computations), then it is neutral, or equal.
english translation
trikoNAt svAtsukhasvA'ntyadhIdharmAyuHsvatuGgapAH। suhRdo ripavazvAnve samAzcobhayalakSaNAH॥ 55॥
hk transliteration by Sanscript