Shiva Purana
तत्तद्देवान्समुद्दिश्य सांगं कुर्य्याद्विचक्षणः॥ एवमग्निमुखाद्यं यत्कर्मतन्त्रम्प्रवर्त्तितम् ॥ २०॥
A wise man should chant the Sangam in the name of the respective devas. Thus the system of rituals beginning with the mouth of fire was introduced.
english translation
tattaddevAnsamuddizya sAMgaM kuryyAdvicakSaNaH॥ evamagnimukhAdyaM yatkarmatantrampravarttitam ॥ 20॥
hk transliteration by Sanscript