RT Journal Article SR Electronic T1 A Discussion of the Methods used for Measuring Roentgen-Ray Applied Intensity JF Cleveland Clinic Journal of Medicine JO Cleve Clin J Med FD Cleveland Clinic SP 42 OP 51 VO 1 IS 1 A1 U. V. Portmann YR 1931 UL http://www.ccjm.org/content/1/1/42.abstract AB