Shivapurana 6.5.26

Śivapurāṇa (complete text) 6.5.26

caturasraṃ kramātteṣu likhedbījaṃ catuṣṭayam |
pūrve binduṃ samālikhya śubhraṃ kṛṣṇaṃ tu dakṣiṇe ||