1. When are cyclists going to wear helmets?;Lancet,1988
2. et al Head injuries in moped and bicycle collisions: Implications for bicycle helmet design IRCOBI Conference 1985;Walz, H.W.
3. Impact performance of bicycle helmets;Bishop, P.J.; Briard, B.;Can J Appl Sport Sci
4. Standard method of impact test and performance requirements for football helmets;N.O.C.S.A.E.,1985
5. NOCSAE football helmet certification program;Hodgson, V.R.;Medicine & Sci in Sports,1975