Vedavyasasmriti 9

9

vaiśyāsa viprakṣatrābhyāṃ tataḥ śūdrāsu śūdravat .
adhamāduttamāyāntu jātaḥ śūdrādhamaḥ smṛtaḥ .. 1.8 ..

On vaiśya women by a brahmin and a kṣatriya; then on śūdra women, like a śūdra. / One born of a low [man] on a higher [woman] is considered lower than a śūdra. // 1.8