Brihat Parashara Hora Shastra
व्ययेशेन युतो भौमो गुरुणा सहितोऽपि वा। भ्रातृभावे स्थिते चन्द्रे सप्तसंख्यास्तु सोदराः॥ १२॥
There will be 1 co-born, if Vyaya‟s Lord (some texts read, as Labh‟s Lord) joins Mangal and Guru, while Sahaj Bhava is occupied by Candr.
english translation
vyayezena yuto bhaumo guruNA sahito'pi vA। bhrAtRbhAve sthite candre saptasaMkhyAstu sodarAH॥ 12॥
hk transliteration by Sanscript