Brihat Parashara Hora Shastra
शुभाऽशुभं ग्रहाणां च समीक्ष्याऽथ बलाऽबलम् । तुङ्गस्थाने विशेषेण बलं ज्ञेयं तथा बुधैः ॥ ३९॥
The good and bad effects of Grahas should be deciphered, based on the strength and weakness of the Grahas. In exaltation the Grahas reveal effects in a pronounced manner, due to Avasthas.
english translation
zubhA'zubhaM grahANAM ca samIkSyA'tha balA'balam । tuGgasthAne vizeSeNa balaM jJeyaM tathA budhaiH ॥ 39॥
hk transliteration by Sanscript