::Thanks for the list. It'll have to do for now. Regarding global t's, all I'm looking for is a simple definition of the term. I don't want to try to formulate a definition myself after having read through "various papers."  I just want to be directed to a credible reference source where said definition can be found. Surely such a source must exist. If not, I'll have no choice but to assume that the term, despite all protestations to the contrary is, in fact, utterly devoid of any scientific meaning. Again, thanks for any help you can provide.