Vaishnava Dharmashastra 21.22

21.22

sapiṇḍīkaraṇaṃ strīṇāṃ kāryam evaṃ tathā bhavet
yāvaj jīvaṃ tathā kuryāc chrāddhaṃ tu prativatsaram //

The ceremony of investing women with the relationship of Sapinda has to be performed in the same manner. Later, he must perform a Srâddha every year, while he lives, (on the anniversary of the deceased relative's death).