This one is from Bill Patry’s excellent blog:
“…for copyright geeks, the traditional Happy Birthday has provided fodder for what all that is wrong with copyright. Now, Professor Robert Brauneis of George Washington Law School has blessed us with an exhaustive treatment of the song.”
Here’s the link to the article, “Copyright and the World’s Most Popular Song“: http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1111624
According to Patry “The article is a tour de force of historical research as well as a probing inquiry into how copyright works that have fallen into the public domain can still command serious income through the inability of others to spend the time and money to track down the provenance of the claims to copyright in them. ”
Time to make coffee and start reading: “67 and a half pages of history of the song and the copyright issues surrounding it.” Happy Birthday.