Shiva Purana
शिवश्चैव च रेखायास्तृतियायाश्च देवता । विज्ञेया मुनिशार्दूल शिवदीक्षापरायणौ ९४ ।
And Śiva is the deity of the third line. O foremost among sages, this must be carefully understood by those initiated in the cult of Śiva.
english translation
zivazcaiva ca rekhAyAstRtiyAyAzca devatA । vijJeyA munizArdUla zivadIkSAparAyaNau 94 ।
hk transliteration by Sanscript