Troyano, Leonardo Fernández (2003). "Singular Bridges". Bridge Engineering: A Global Perspective(Google books (preview)). London: Thomas Telford. p. 708. ISBN978-0-7277-3215-6. Retrieved May 23, 2009. A folding footbridge designed by Von Gerkan, Marg und Parter was recently built in the Port of Kiel with a 25.5-metre span.
