
“New Shapes for Shells.” (1960) Bulletin of the International Association for Shell Structures, no.8, Paper C-3, taken from Tessa Maurer, Elizabeth O'Grady, Ellen Tung, "Inverse Hanging Membrane: Naturtheater Grötzingen" http://shells.princeton.edu/Grotz.html ( 2013) Evolution of German Shells Forms: Efficiency of Form, Princeton University Dept. Civil and Environmental Engineering.