When I looked at the Cato edit, it was simply a removal of the reference, the addition of another donor, and a change in the language. Without an edit summary to explain, the changes were unjustified. (Your clarification certainly helps.) Thanks, also, for adding the reference on Summers. Frankly, I did not look at the sources removed or added. My main concern was the unexplained edits. Summaries are important! And then I saw that the messages about these same concerns from a while back, so my message is more of a reminder. Most importantly, you are incorrect if you think it is "not against the rules to add unsourced material". One of the core content policies is WP:V, and WP:RS allows us to carry out that policy. Happy editing. –