The Ground of Arts
Robert Recorde's Arithmetic: or, The Ground of Arts was one of the first printed English textbooks on arithmetic and the most popular of its time. It introduced the equals sign ("="). It was preceded only by two anonymous texts in 1537 and 1539; The Ground of Arts appeared in London in 1543, and it was reprinted around 45 more editions until 1700. Editors and contributors of new sections included John Dee, John Mellis, Robert Hartwell, Thomas Willsford, and finally Edward Hatton.
- Bregman, Alvan (1 July 2005). "Alligation Alternate and the Composition of Medicines: Arithmetic and Medicine in Early Modern England". Med. Hist. 49 (3): 299–320. doi:10.1017/s0025727300008899. PMC 1172291. PMID 16092789.
- Karpinski, Louis (1925). The history of arithmetic. Rand McNally. LCC QA21.K3.
- Recorde, Robert (1543). The Grounde of Artes. London: Reynold Wolff. LCC QA33.R3 1542a.
- Recorde, Robert (1699) . Edward Hatton (ed.). Arithmetick, or, The ground of arts. London: J.H. for Charles Harper.