Phaladeepika
जन्मनक्षत्रनाथस्य प्रत्ययर्क्षर्धिपस्य च स्फुटयोगं गते जीवे त्रिकोणे वा सुतोद्भवः ॥ ३०॥
Note the ruler of the asterism occupied by the Moon as also that of the 5 th from it. Add the figures of these two planets. When Jupiter in his orbit passes through the sign represented by this result or through one of its triangular ones, the birth of a son is possible.
english translation
janmanakSatranAthasya pratyayarkSardhipasya ca sphuTayogaM gate jIve trikoNe vA sutodbhavaH ॥ 30॥
hk transliteration by Sanscript