Shiva Purana
षड्दिनान्यादितः कृत्वा संख्यायाश्च यथाविधि ॥ एतदंतर्गते चैव वामरंध्रे प्रकाशितम् ॥ ५१॥
Beginning with six days and calculating duly it happens at mentioned in the left path.
english translation
SaDdinAnyAditaH kRtvA saMkhyAyAzca yathAvidhi ॥ etadaMtargate caiva vAmaraMdhre prakAzitam ॥ 51॥
hk transliteration by Sanscript