Shiva Purana
सप्तविंशद्दिनमितं वहतेत्यतिविश्रमा ॥ मासमेकं समाख्यातं जीवितं वामगोचरे॥ ४८॥
If it respires for twenty-seven days incessantly he lives for a month.
english translation
saptaviMzaddinamitaM vahatetyativizramA ॥ mAsamekaM samAkhyAtaM jIvitaM vAmagocare॥ 48॥
hk transliteration by Sanscript