Yāska's Nirukta 77.1.2

77.1.2

vāyuratrāpradhānam, kasmāt 'tṛtīyo bhrātā ghṛtapṛṣṭhaḥ asya'- ityeṣaḥ "asya"-śabdo'nudāttaḥ || evamekasminnevāsmin mantre udāttānudāttāvetau asya-śabdau pradhānāpradhānaviṣayāvityekamevodāharaṇam || āha- 'tṛtīyo bhrātā ghṛtapṛṣṭho asya'- ityanena "asya"-śabdena sūrya eva kasmānna sambadhyate ? api ca "tṛtīya"-śabdasya prakṛtānukramāvirodhenaivameva suvyantarā yojanā bhaviṣyati | ucyate-'asya vāmamya' ityetadantodāttaṃ padamitaradanyat 'tṛtīyo bhrātā ghṛtapṛṣṭhaḥ asya'- iti samānarūpameva sat pūrveṇānudāttamiti svarakṛtādviśeṣādarthakṛtenāpi viśeṣeṇa bhavitavyamityapradhānābhidhāyinā viśeṣaḥ pratīyate | ādityamantratvāt sūkte vāyuścātrāpradhānaḥ prakṛtādādityāt | tasmādvāyuviṣayamevedam asyeti dvitīyaṃ padamanudāttaṃ sampadyate | ataḥ sutarāmupapannaṃ bhavati "udāttaṃ prathamādeśe 'nudāttamanvādeśe"-ityatra prathamādeśanvādeśaśabdābhyāṃ pradhānāpradhānāvucyete iti || anye tu manyante, prathamādeśo nāma prārambhaḥ, tatra yadvarttate, tadudāttaṃ bhavati, pradhānārthetaramudāttamityanenaiva lakṣaṇena | tadyathā, "a̱syā ū̱ ṣu ṇaḥ (ṛ0 sa0 2, 2, 2, 4)", "a̱sya vā̱masya̍ (ṛ0 sa0 2, 3, 17, 1)"-iti || anvādeśo nāma, anyasya padasya paścādādeśaḥ, tatra varttamānamanudāttaṃ bhavati | padāt parasya nighāto bhavatīti hi lakṣaṇavido'pi bruvate | tathānnudāttatvenaiva lakṣaṇenālpīyāṃ'rthatamapradhānādyaṃtaraṃ bhavati | tadyathā, "dīrghāyurasyā yaḥ patiḥ (ṛ0 sa0 8, 3, 27, 8)" 'tṛ̱tī̱yo bhrātā̍ ghṛ̱tapṛ̍ṣṭho asya (ṛ0 sa0 2, 3, 17, 1)" iti || āha kathaṃ saptamaputra ādityaḥ ? iti |