Markandeyapurana 30.16

30.16

kuryāt pitṝṇāṃ tritayamekaṃ pretasya putraka /
pātratraye pretapātramarghyañcaiva prasecayet //

“And there is another distinction, consisting in an extra ceremony every month; do thou listen attentive to me, as I tell thee of it, while it is being described. He should fill four vessels there with sesamum-seed, perfume and water, three for the pitṛs, one for the deceased person, my son. And he should scatter the arghya-oblation in the three vessels, and in the deceased’s vessel,[6] uttering the words ‘Ye samānā’ &c., he should perform the rest as before.