Manusmriti
वैतानिकं च जुहुयादग्निहोत्रं यथाविधि । दर्शमस्कन्दयन् पर्व पौर्णमासं च योगतः ॥ ९ ॥
Let him offer, according to the law, the Agnihotra with three sacred fires, never omitting the new-moon and full-moon sacrifices at the proper time.
english translation
vaitAnikaM ca juhuyAdagnihotraM yathAvidhi । darzamaskandayan parva paurNamAsaM ca yogataH ॥ 9 ॥
hk transliteration by Sanscript