1. Duplication of roentgenograms by the light reversal process;Henry;Am J Roentgenol,1943
2. Duplication of radiographs by solarisation;Illingworth;Br J Radiol,1946
3. Reproduction of radiographs by a reversal process;Marshall;Radiography,1952
4. A special technique to retrieve images from a dark cephalogram;Thunthy;J Am Dent Assoc,1985
5. Duplication of radiographs;Thunthy;Quintessence J,1980