THEORY: Tonogenesis

I'm looking for help on the mechanism of tonogenesis,
since I think I want to try a tonal language (maybe
developing from some lang I already have). A Web search
has been remarkably poor in results, so I'd thank anyone
who can tell me about tonogenesis, or give me some
pointers.

The one resource I've found is

    A Critical Review of Norman's _Chinese_
    Marjorie K.M. Chan and James H.Y. Tai

and it says that the presence of [?] and [h] in codas
may have something to do with pitch rising and lowering,
respectively, and mentions an "entering tone" (which, I
seem to remember, has something to do with the voicing
of the onset consonant).

Thanks in advance,


--Pablo Flores
  http://www.geocities.com/pablo-david/index.html
  ... I cannot combine any characters that the divine Library
  has not foreseen, which in some of its secret tongues do not
  bear some terrible meaning. No-one can articulate a syllable
  not filled of caresses and fears; which is not, in some one
  of those languages, the powerful name of a god...
                   Jorge Luis Borges, _The Library of Babel_