Question about Clark Still's Generalized Born Solvation Model

 Dear Netters,
 Two questions about the GB solvation Model available in Macromodel:
 1.  The procedure uses the SA ("Surface Area") as a parameter in
 the solvation free energy.  What algorithm does Macromodel use to calculate
 this SA term for a given molecule.  Is this procedure published somewhere in
 a detailed manner?
 2.  I seem to remember that Clark Still, et al., published an article
 in JACS or in the J. Comput. Chem. which describes the Generalized Born method.
 Can someone cite this (these) references for me?
 Thanks for any feedback ....
 Bill Welsh
 Dept. of Chemistry
 Univ. of Missouri-St. Louis