Brihat Parashara Hora Shastra
तृतीयमष्टमस्थानमायुःस्थानां द्वयं द्विज । मारकं तद्व्ययस्थानं द्वितीयं सप्तमं तथा ॥ २॥
O Brahmin, Sahaj and Randhr Bhava are the two Bhavas of longevity. The Bhavas, related to death, are the 12th from each of these, i.e. Dhan and Yuvati Bhava are Marak Bhavas.
english translation
tRtIyamaSTamasthAnamAyuHsthAnAM dvayaM dvija । mArakaM tadvyayasthAnaM dvitIyaM saptamaM tathA ॥ 2॥
hk transliteration by Sanscript