If a book that has been accessed online does not have DOI, then the citation ends with the URL of the provider's website, EVEN if you actually retrieved the book through the TRU Library Catalogue.
Template
Author A. A. (Year). Title of work. Retrieved from http://...
Examples:
Austen, J. (1815). Emma. Retrieved from http://www.gutenberg.org
Goldman, E. (1914). Marriage and love. Retrieved from http://www.hathitrust.org
Halberstam, J. J. (2012). Gaga feminism: Sex, gender, and the end of normal. Retrieved from http://www.books.google.ca
Richardson, D. (2000). Rethinking sexuality. Retrieved from http://www.ebrary.com