Gopathabrahmana 1.1.5

1.1.5

tam atharvāṇam ṛṣim abhyaśrāmyad abhyatapat samatapat
tasmāc chrāntāt taptāt saṃtaptād daśatayān atharvaṇa ṛṣīn niramimataikarcān dvyṛcāṃs tṛcāṃs caturṛcān pañcarcānt ṣaḍarcānt saptarcān aṣṭarcān navarcān daśarcān iti [ed.: ṣaḍarcāṃt]
tān atharvaṇa ṛṣīn abhyaśrāmyad abhyatapat samatapat
tebhyaḥ śrāntebhyas taptebhyaḥ saṃtaptebhyo daśatayān ātharvaṇān ārṣeyān niramimataikādaśān dvādaśāṃs trayodaśāṃś caturdaśān pañcadaśān ṣoḍaśānt saptadaśān aṣṭādaśān navadaśān viṃśān iti [ed.: ṣoḍaśāṃt, note also pañcarcānt above]
tān atharvaṇa ṛṣīn ātharvaṇāṃś cārṣeyān abhyaśrāmyad abhyatapat samatapat
tebhyaḥ śrāntebhyas taptebhyaḥ saṃtaptebhyo yān mantrān apaśyat sa ātharvaṇo vedo 'bhavat
tam ātharvaṇaṃ vedam abhyaśrāmyad abhyatapat samatapat
tasmāc chrāntāt taptāt saṃtaptād om iti mana evordhvam akṣaram udakrāmat
sa ya icchet sarvair etair atharvabhiś cātharvaṇaiś ca kurvīyety etayaiva tan mahāvyāhṛtyā kurvīta
sarvair ha vā asyaitair atharvabhiś cātharvaṇaiś ca kṛtaṃ bhavati ya evaṃ veda yaś caivaṃvidvān evam etayā mahāvyāhṛtyā kurute || 5 ||