@book{6540, author = {Katz, David L.,}, title = {Jekel's Epidemiology, Biostatistics, Preventive Medicine, and public health }, publisher = {Saunders,}, year = {c2014.}, address = {Philadelphia, Pa. ;}, edition = {4th ed.}, note = {Formal title: Epidemiology, biostatistics, preventive medicine.} }