Matsyapurana 17.64

17.64

bhāryāvirahito 'pyetat pravāsastho 'pi bhaktimān
śūdro 'pyamantravatkuryād anena vidhinā budhaḥ //

This form of Sâdhâraṇâ śrâddha can be performed even by those, who have not been invested with the sacred thread, those who are in a foreign country and have not their wives with them. The Sûdras may also perform it without reciting any sacred formulae.—63-64.