Brihat Parashara Hora Shastra
ग्रहस्थितिवशाज्ज्ञेयं द्विराश्यधिपतिस्तथा। मध्येऽनुपाततो ज्ञेयं ओजयुग्मर्क्षभेदतः॥ १२॥
In between the strength be known by the rule of three process. In the case of a Grah, owning two Rāśis, distinction of placement in odd/even Rāśi identical with own Rāśi be made.
english translation
grahasthitivazAjjJeyaM dvirAzyadhipatistathA। madhye'nupAtato jJeyaM ojayugmarkSabhedataH॥ 12॥
hk transliteration by Sanscript