1. About the cover: Early American arithmetics
2. Extension of Huygens’ Approximation to a Circular arc
3. 2. John Bonnycastle on the MacTutor History of Mathematics archive https://www-history.mcs.st-and.ac.uk/Biographies/Bonnycastle.html (accessed 01/11/2019).
4. 1. Bonnycastle, J. , Introduction to mensuration and practical geometry, American edition (1812). Available on-line at https://archive.org/details/Bonnycastle/page/n4 (accessed 01/11/2019).