Brihat Parashara Hora Shastra
मेषमीनादितो जन्मलग्नान्तं गणयेत् सुधीः। तथैव होरालग्नान्तं गणयित्वा ततः परम्॥ १२॥
If both the products are odd Rāśis, or even Rāśis, then add both the figures. If one is odd and the other is even, then know the difference between the two products.
english translation
meSamInAdito janmalagnAntaM gaNayet sudhIH। tathaiva horAlagnAntaM gaNayitvA tataH param॥ 12॥
hk transliteration by Sanscript