Huijbers, J. J. W. (1990). Utilisation of security helmets for two-wheeled vehicle riders. Institute for Road Safety Research SWOV, The Netherlands.
Lua i Stíl Chicago (17ú heag.)Huijbers, J. J. W. Utilisation of Security Helmets for Two-wheeled Vehicle Riders. Leidschendam: Institute for Road Safety Research SWOV, The Netherlands, 1990.
Lua MLA (9ú heag.)Huijbers, J. J. W. Utilisation of Security Helmets for Two-wheeled Vehicle Riders. Institute for Road Safety Research SWOV, The Netherlands, 1990.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.