my @files= <*>;
@files= do {
    my @mo= ( qw(Jan Feb Mar Apr May Jun
        Jul Aug Sep Oct Nov Dec), 'a'..'l' );
    my %mo; @mo{@mo}= reverse @mo;
    grep {
        s/^(.)/$mo{$1}/
    } sort grep {
        s/^(...)/$mo{$1}/
    } @files;
};

##</code><code>##

my @files= <*>;
@files= do {
    my @mo= qw(jan feb mar apr may jun
        jul aug sep oct nov dec);
    my %mo; @mo{@mo}= 0..$#mo;
    grep {
        s/^[^-]*-//
    } sort grep {
        # Replace "JAN1" with "a01-JAN1":
        s/^(...)(\d\d?)/sprintf
            "%s%02d-%s",$mo{lc$1},$2,$1.$2/e
            or  $_= "?-$_";
        1;
    } @files;
};