RT Journal Article SR Electronic T1 Astronavigation JF Journal of the Royal Army Medical Corps JO J R Army Med Corps FD British Medical Journal Publishing Group SP 312 OP 315 DO 10.1136/jramc-96-05-09 VO 96 IS 5 A1 F. M. Richardson YR 1951 UL http://militaryhealth.bmj.com/content/96/5/312.abstract AB