Hi grammarians!
Can someone please tell me the latest rule regarding the use of
the last comma in a series?  Some of my grammar books say that
one must include it in formal writing, while not in informal writing
such as journalism; others say that the last comma is needed
only if misreading would occur without it, as in
 
We elected our president, vice president, secretary and
treasurer.
 
        I think your close.  It should ready:  We elected out president,
        vice president, secretary, and treasurer.  If you leave out
        the comma, secretary and treasurer, could be conceived as one
        person.
 
        Michael A. Burris
        Bedford, Massachusetts
 
        P.S.  Can't quote the exact rule, but it seems to make sense.