MLA

Sadler, John, d. ca. 1595, Vegetius Renatus, Flavius., creator. The fovre bookes of Flauius Vegetius Renatus: briefelye contayninge a plaine forme, and perfect knowledge of martiall policye. Anno. 1572. https://collections.library.yale.edu/catalog/2110916.

APA, 6th edition

Sadler, John, d. ca. 1595, & Vegetius Renatus, Flavius., creator. (Anno. 1572)[The fovre bookes of Flauius Vegetius Renatus: briefelye contayninge a plaine forme, and perfect knowledge of martiall policye]. https://collections.library.yale.edu/catalog/2110916.