ISBN 952-5446-11-5. ↑ Alan Jefferis, David A. Madsen Architectural Drafting and Design (Cengage Learning, 2004) ISBN 1-4018-6715-4, pages 35-36 ↑ N.D.Bhatt Engineering Drawing Plane and Solid Geometry (Charotar Publishing House, 2012), pages 12-13 ↑ "Perspective Machine", The New and Complete American Encyclopedia, John Low, 1810, p.