phos.pde
  This is an implementation of the 5-species model described in the
  following reference.


@ARTICLE{
richardson:apl,
AUTHOR = "W. B. Richardson and B. J. Mulvaney",
TITLE = "Plateau and kink in P profiles diffused into Si: A result
of strong bimolecular recombination?",
JOURNAL = APL,
VOLUME = 53,
NUMBER = 20,
YEAR = 1988,
MONTH = nov,
PAGES = "1917--1919"
}