Head Injury in SportBMJ 308:1620-1624, McLatchie,G.&Jennett,B., 1994
Helmet Use and Risk of Head Injuries in Alpine Skiers and SnowboardersJAMA 295:919-924, Sulheim,S.,et al, 2006
Head InjuryJNNP 58:526-539, Teasdale,G.M., 1995