Kurmapurana 2.19.14

Kūrmapurāṇa 2.19.14

yajñopavītī bhuñjīta straggandhālaṅkṛtaḥ śuciḥ /
sāyaṃprāparnāntarā vai saṃdhyāyāṃ tu viśeṣataḥ //