Image quality assurance in X-ray departments – Part 13: Constancy testing of projection radiography systems with digital image receptors
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 02/01/2003

Image quality assurance in diagnostic X-ray departments РPart 13: R̦V constancy test of projection radiography systems with digital image receptors
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 03/01/2012