Grammatical Sūtra: वैवावेति च च्छन्दसि vaivāveti ca cchandasi 
Individual Word Components: vaivāva (luptaprathamāntanirdeśaḥ) iti ca chandasi
Sūtra with anuvṛtti words: vaivāva (luptaprathamāntanirdeśaḥ) iti ca chandasi padasya (8.1.16), padāt (8.1.17), anudāttam (8.1.18), sarvam (8.1.18), apādādau (8.1.18), tiṅ (8.1.28), na (8.1.29), prathamā (8.1.59), kṣiyāyām (8.1.60), vibhāṣā (8.1.63)
Type of Rule: pratiṣedha
Preceding adhikāra rule:8.1.18 (1anudāttaṃ sarvam apādādau)
Description:
Also in connection with ((vai)) and ((vāva)), may optionally, in the Chhandas, the first verb retain its accent. Source: Aṣṭādhyāyī 2.0
In the domain of Chándas [the first 59 verbal padá 28 is not 29 all ánudātta 18 optionally 63 when co-occurring with 30] the particles vaí and vāvá. Source: From Aṣṭādhyāyī of Pāṇini In Roman Transliteration translated by Sumitra M. Katre, Copyright © 1987. Courtesy of the University of Texas Press.