I am not absolutely positive about this but I think that your sources are general because that is the truth. Salsa music comes in many differing "flavors"...there is Cuban salsa, as well as Puerto Rican, New Yorican, Mexican and Panamanian. The dialects of the latin american music all differ slightly as does the style of salsa that these different nationalities dance. I think, that salsa developed independetly with the music all over south america, so there is no one "origin". Much of the popular music that I have heard at competitions seems to be Cuban or Puerto Rican...I suppose that the style of salsa danced in competition is probably adapted from one countries particular style of salsa...but again, I'm not sure. So, I hope someone else can answer this question better...but just a note as to why your references may be so vague sounding.