General format for an Ebook:

Author(s). Title of book. Edition. Place of publication: publisher; date of publication [date updated; date accessed]. Notes.

Example:

Griffiths AJF, Miller JH, Suzuki DT, Lewontin RC, Gelbart WM.  Introduction to genetic analysis.  7th ed. New York (NY): W. H.   Freeman & Co.; c2000 [accessed 2005 May 31].  http://www.ncbi.nlm.nih.gov/books/bv.fcgi?call=bv.View..ShowTOC&      rid=iga. TOC. 

Chapter in an ebook where each chapter has an individual author:

Author(s) .Chapter title. In: Editors(s), editors. Title [Internet]. Place of publication: publisher, year [cited date]. Extent.  Notes.

Aldridge S. Malaria. In: Lerner BW, Lerner KL, editors. Infectious diseases: in context [Internet]. Detroit: Gale; c2008 [cited 2010 May 5]. p. 515-522. Available from: http://go.galegroup.com/ps/i.do?id=GALE|1RIG&v=2.1&u=seattlepu&it=aboutBook&p=GVRL&sw=w.