Angirasasmriti 2.4.5

2.4.5

sāvitrīmātrasāraistu cīrṇavedavratairdvijaiḥ /
yatīnāmātmavidyānāṃ dhyāyināmātmavedinām /
śirovrataiśca snātānām eko 'pi pariṣadbhavet //

Or by twice-born men whose essence is only the Sāvitrī verse, who have performed their Vedic vows; / of ascetics knowledgeable in the Self, meditating, knowers of the Self, / and bathed by the rite of the head-vow—even one may constitute an assembly.