Parks Canada Design Guidelines for Media Accessibility?

In many publications about museum accessibility or universal design, I see references to “Design Guidelines for Media Accessibility” from Parks Canada. Some tables in the Smithsonian Guidelines for Accessible Exhibition Design are copied directly from the Parks Canada publication.

But I can’t find a copy of “Design Guidelines for Media Accessibility” anywhere. (I have searched my university library, Amazon, Amazon.ca, Google Books, the Parks Canada website, and the web more generally, with no luck.) Nor can I find anything that might have served as the primary source for their recommendations about font proportions and sizes.

Does anyone know where I can get a copy of the Parks Canada guidelines? Or have recommendations for primary source material for the font recommendations? I am hoping to develop accessibility guidelines for our museum; basing the guidelines on a document that got the information from another document that got the information from we-don’t-know-where is not going to persuade folks that our minimum type size should be 24 point.