Since many eBooks do not have page numbers, the chapter number is sufficient for the page number field.
Example:
Durrani TS, Olson KR. Medical toxicology. In: Ladou J, Harrison RJ eds. CURRENT Diagnosis and Treatment: Occupational & Environmental Medicine. 5th ed. New York, NY: McGraw Hill; 2013: chap 16. Accessed October 23, 2019. http://accessmedicine.mhmedical.com
eBooks (3.12.11)
eBooks are cited in the same manner as regular books with the addition of an assessed date and link.
Example:
Guyatt G, Rennie D, Meade MO, Cook DJ. Users' Guides to the Medical Literature: A Manual for Evidence-Based Clinical Practice. 3rd ed. McGraw-Hill Education; 2015. Accessed August 15, 2016. https://jamaevidence.mhmedical.com/book.aspx?bookID=847
Books (3.12)
Complete book references including the following:
Authors’ surnames and initials (All listed unless more than 6, in that case list first 3 and "et al")
Title of book and subtitle, if any
Volume number and volume title, when there is more than one volume
Edition number (do not indicate first edition)
Name of publisher
Year of copyright
Page numbers, when specific pages are cited
Examples:
Silverstein A, Silverstein VB, Nunn LS. Cancer. Twenty-First Century Books; 2006.
Maul-Mellott SK, Adams JN. Childhood Cancer: A Nursing Overview. Jones and Bartlett; 1987.