This comes up from time to time - usually in the form of "Buzan didn't invent mind mapping".
Here are links to important scholarly papers by Joseph D. Novak and Alberto J. Cañas on Concept Maps, their theory and construction.
"Semantic network" is a broad enough term to cover many forms of information map. Here is a link to an article by John F. Sowa, originally written for the Encyclopedia of Artificial Intelligence.
Here are some links to articles on the visual representation of knowledge by Sigmar-Olaf Tergan, an academic leader in the field
This is a 1997 article by Eric Plotnick, from the ERIC Clearinghouse on Information and Technology Syracuse NY