References ^ (1991). 9780881676952, Raven Press. ISBN 9780881676952 (revised Dec 2013)^ Norman Kretchmer, Angel Ballabriga, Buford L. NicholsHistory of Pediatrics, 1850-1950 Vol. 22 by Norman Kretchmer, Angel Ballabriga and Buford L. Nichols (1990, Book, Other) ISBN 9780881676952 (revised Apr 2015)