Model No. 221 FA:
Description: Areas and curves of constant width and constant perimeter; in addition straps to push through
RE: S 107, 148,149; M3 319,325,339,347 Jessen: Über konvexe Punktmengen konstanter Breite. Math. Zeitschrift B 29 Heft 2/3 Category:
RU: E VI 13-25