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Maartens, N. F.; Wills, A. D.; Adams, C. B. (2002). "Lawrence of Arabia, Sir Hugh Cairns, and the origin of motorcycle helmets". Neurosurgery. 50 (1): 176–9, discussion 179-80. doi:10.1097/00006123-200201000-00026. PMID11844248. S2CID28233149.
Maartens, N. F.; Wills, A. D.; Adams, C. B. (2002). "Lawrence of Arabia, Sir Hugh Cairns, and the origin of motorcycle helmets". Neurosurgery. 50 (1): 176–9, discussion 179-80. doi:10.1097/00006123-200201000-00026. PMID11844248. S2CID28233149.