Caparrini, Sandro. (2000). «On the Common Origin of Some of the Works on the Geometrical Interpretation of Complex Numbers» in Kim Williams Two Cultures. Birkhäuser, 139 or. ISBN978-3-7643-7186-9.. Extract of page 139
Extracted quotation from "A Short History of Complex Numbers", Orlando Merino, University of Rhode Island (January, 2006) http://www.math.uri.edu/~merino/spring06/mth562/ShortHistoryComplexNumbers2006.pdf