Gobhilagrihyasutra 2.8.14

2.8.14

āhaspatyaṃ māsaṃ praviśā 'sāv ity ante ca mantrasya ghoṣavadādy antarantasthaṃ dīrghābhiniṣṭhānāntaṃ kṛtaṃ nāma dadhyāt:

In (the passage of the Mantra), 'Enter upon the month, that belongs to Ahaspati (i.e. the lord of days), N.N.!' and at the end of the Mantra he should give him a name beginning with a sonant, with a semivowel in it, with a long vowel or the Visarga at the end, (and formed with) a Krit (suffix).