Count multiple conditions array only works with 1 value

I have a file (attached) of articles with titles and multiple authors (if more than one contributed to the article).
I need to count the number of times one author co-authored an article with another author.
I thought a table/array of all author names vertically as table row names with same names across the top as column labels and the number of times they've co-authored in the cells beneath.

Perhaps I need a macro (not sure how to do that) but I thought an array formula might work. It works for the first author but not thereafter.
Suggestions are greatly appreciated!