Phaladeepika
लग्नादिकानामधिपस्य पिण्डे रूपान्विते तद्बलपिण्डमाहुः । गृहस्य यस्यां दिशादिग्बलं स्यात्तद्भाववीर्य सहितस्य दृष्ट्या ॥ २४॥
In the case of the Lagna and other Bhavas, add one Rupa to the strength of the lord of the Bhava concerned Supplement this by the Directional strength (Digbala) due to that Bhava and also by the strength of aspect Drigbala of that Bhava. The aggregate sum - total is the Bhavabala required.
english translation
lagnAdikAnAmadhipasya piNDe rUpAnvite tadbalapiNDamAhuH । gRhasya yasyAM dizAdigbalaM syAttadbhAvavIrya sahitasya dRSTyA ॥ 24॥
hk transliteration by Sanscript