1855, Austin Flint, Clinical Reports on Continued Fever Based on Analyses of One Hundred and Sixty-Four Cases, Linday & Blakiston, First Clinical Report on Continued Fever, Based on an Analysis of Forty-Two Cases, page 39
1921, Charles Signmund Raue, Diseases of Children - Homeopathic Treatment, 2nd edition, B. Jain Publishers, published 2000, Chapter IX Diseases of the Intestines, pages 205–206