Brihat Parashara Hora Shastra · Chapter 71

athā'ṣṭavargāyurdāyādhyāyaḥ

athātrāyuḥ pravakṣye'hamaṣṭavargasamudbhavam /
dinadvayaṃ virekhāyāṃ rekhāyāṃ sārdhavāsaram

dinamekaṃ dvirekhāyāṃ trirakhāyāṃ dinārdhakam /
vedatulyāsu rekhāsu sārdhasaptadinaṃ smṛtam

dvivarṣaṃ pañcarekhāsu ṣaḍrekhāsu catuḥsamā /
ṣaḍvarṣaṃ saptarekhāsu vasavo'ṣṭāsu vatsarāḥ

evaṃ yadāgatāyuḥ syāt sarvakheṭasamudbhavam /
tadardhaṃ sphuṭamāyuḥ syādaṣṭavargabhavaṃ nṛṇām