Yājñavalkya Śikṣā 18

18

sāvitrīṃ cānupūrvyeṇa tato vedānsamārabhet
hastau tu saṃyyatau dhāryyau jānvorupari saṃsthitau

and the Sāvitrī verse in proper order; then one should begin the Vedas. / The hands should be held restrained, resting upon the knees;