1. Kahn J, inventor. Trussed Concrete Steel Co, assignee. Floor construction, US patent 926,497, June 29; 1909.
2. Hardison RM, inventor. Kalman Steel Co, assignee. Flat slab construction, US Patent 1,550,317, August 18; 1925.
3. Shearhead reinforcement for slabs;Corley;ACI J Proc,1968
4. Composite shear head systems for improved punching shear resistance of flat slabs;Piel;Compos Constr Steel Concr V,2006
5. Tuchschmid-WALM Dokumentation – Stützenkopfverstärkung – Optimale Krafteinleitung auf tragende Stützen;Tuchschmid,2007