I've just run across this on the web; apparently Hristo Bonev, Bulgarian legend, 'came out of retirement in 1982 to play for Oxford United'. This is repeated on several sites, with no further information. It sounds extraordinarily unlikely- did Jim Smith regularly scout the Balkans?- but is it actually true? He certainly didn't make a competitive appearance, and the story sounds like an urban myth- perhaps he played up front in a couple of pre-season friendlies with Bob Holness? Still, if anyone can give a definitive yes or no...