Shiva Purana

siva.sh/siva-purana/kotirudra-samhita/28/8

एकैकं च शिरश्छिन्नं विधिना शिवपूजने ।। एवं सत्क्रमतस्तेन च्छिन्नानि नव वै यदा ।। ६ ।।

sanskrit

Each of the heads was cut off in accordance with the rituals in the worship of Lord Shiva. When he had thus cut off nine of them in good order.

english translation

ekaikaM ca zirazchinnaM vidhinA zivapUjane || evaM satkramatastena cchinnAni nava vai yadA || 6 ||

hk transliteration by Sanscript