In this context "other literature resources" refers specifically to documents (PDF) published by an organisation and placed on the Internet. Such a document cannot be an Internet resource and it usually does not contain all the information that would have it classified as a book. The prescribed reference is as follows:
Footnote
1 Food and Agriculture Organisation of the United Nations Guide on Legislation for the Right to Food 23.
Bibliography (under the heading "Literature")
Food and Agriculture Organisation of the United Nations Guide on Legislation for the Right to Food (2009) available at http://www.fao.org/3/a-i0815e.pdf accessed 12 April 2015