Shiva Purana
कोष्ठानि कोणभागेषु चत्वार्येतानि सुन्दरि ॥ शुक्लेनापूर्य्य वर्णादि चतुष्कं रक्तधातुभिः ॥ १४॥
O beautiful one there are four cells in the corners Fill the fourth with white and the red metals beginning with the varṇa.
english translation
koSThAni koNabhAgeSu catvAryetAni sundari ॥ zuklenApUryya varNAdi catuSkaM raktadhAtubhiH ॥ 14॥
hk transliteration by Sanscript