Go to 7th Edition Webpage Reference Examples
The author of a webpage is often the company or organization that created the page (known as a group author). This page includes examples of references for webpages with a group author.
Because the material does not include page numbers, you can include any of the following in the text to cite the quotation (from pp. 170–171 of the Publication Manual):
A paragraph number, if provided; alternatively, you could count paragraphs down from the beginning of the document.
An overarching heading plus a paragraph number within that section.
A short title in quotation marks, in cases in which the heading is too unwieldy to cite in full.
Because there is no date and no author, your text citation would include the title (or short title) "n.d." for no date, and paragraph number (e.g., "Heuristic," n.d., para. 1). The entry in the reference list might look something like this:
Heuristic. (n.d.). In Merriam-Webster’s online dictionary (11th ed.). Retrieved from http://www.m-w.com/dictionary/heuristic