ṚV, 1, 31, 2.2 vibhur viśvasmai bhuvanāya medhiro dvimātā śayuḥ katidhā cid āyave //

ṚV, 3, 55, 6.1 śayuḥ parastād adha nu dvimātābandhanaś carati vatsa ekaḥ /

ṚV, 4, 18, 12.1 kas te mātaraṃ vidhavām acakracchayuṃ kas tvām ajighāṃsac carantam /