1. University of Pennsylvania Health System (2007) Radiology Department History. www.uphs.upenn.edu/radiology/depa . Accessed 28 May 2009
2. Cooper DY (2000) Leonard, Charles Lester. In: American National Biography Online. American Council of Learned Societies. Oxford University Press. http://www.anb.org/articles/12/12-00527.html . Accessed 18 May 2009
3. White JW, Goodspeed A, Leonard CL (1896) Cases illustrative of the practical application of the Roentgen rays in surgery. Am J Med Sci 112:125–147
4. Leopold LA (1981) Radiology at the University of Pennsylvania, 1890–1975. University of Pennsylvania Press, Philadelphia, pp 145, 149, 151
5. Linton OW (1999) A century of radiology at the University of Pennsylvania. Department of Radiology, University of Pennsylvania, pp 62, 235