Weiss, 2019, p.108. Weiss, Isette.«Introducing History of Mathematics Education Through its Actors: Peter Treutlein's Intuitive Geometry». A:Hans-Georg Weigand, William McCallum, Marta Menghini, Michael Neubrand, Gert Schubring (eds.). The Legacy of Felix Klein(en anglès). Springer,2019,p.107-116. ISBN 978-3-319-99385-0.