Shiva Purana
चतुर्युगैकसप्तत्या मनोरंतरमुच्यते ॥ कल्पे चतुर्दशैकस्मिन्मनूनां परिवृत्तयः ॥ १६ ॥
Seventyone Caturyugas constitute a Manvantara. In a Kalpa there are fourteen such Manvantaras.
english translation
caturyugaikasaptatyA manoraMtaramucyate ॥ kalpe caturdazaikasminmanUnAM parivRttayaH ॥ 16 ॥
hk transliteration by Sanscript