John Love (1688). “VII : How to cast up the Contents of a Plot of Land”. Geodaesia: or, The art of surveying and measuring land made easy : shewing, by plain and practical rules, how to survey, protract, cast up, reduce or divide any piece of land whatsoever : with new tables for the ease of the surveyor in reducing the measure of land. London: J. Taylor. p. 122. https://books.google.com/books?id=mWZkAAAAMAAJ