Shiva Purana
मासैस्तैरयनं षड्भिर्वर्षं द्वे चायनं मतम् ॥ लौकिकेनैव मानेन अब्दो यो मानुषः स्मृतः ॥ ७ ॥
Six months are considered to be the ayana, and two years are considered to be the ayana. The year which is considered to be a human being by the same worldly standards.
english translation
mAsaistairayanaM SaDbhirvarSaM dve cAyanaM matam ॥ laukikenaiva mAnena abdo yo mAnuSaH smRtaH ॥ 7 ॥
hk transliteration by Sanscript