VENEREAL DISEASE AND THE NEW ARMY

WILLIAM LYSTER
1917 Journal of the American Medical Association  
point to be located must never be less than 30 degrees or greater than 100 degrees, as otherwise the rays are so nearly parallel that great error is possible.
doi:10.1001/jama.1917.25910420004011a fatcat:gjetq2tp5zcyzhkdfmgdxppbju