Shiva Purana
मातृश्राद्धे मातृपितामह्यौ च प्रपितामही ॥ आत्मश्राद्धे तु चत्वार आत्मा पितृपितामहौ ॥ ४१ ॥
In the mother's shraddha the mother's grandmother and the great-grandmother In the self-shraddha the four souls are the fathers and grandfathers.
english translation
mAtRzrAddhe mAtRpitAmahyau ca prapitAmahI ॥ AtmazrAddhe tu catvAra AtmA pitRpitAmahau ॥ 41 ॥
hk transliteration by Sanscript