dtd_src(){
message dtd_src $1 $2 &&
mkdir $SOURCE_DIRECTORY/$1     &&
cd $SOURCE_DIRECTORY/$1        &&
unpack_file $2                 &&
patch -p0 < $SCRIPT_DIRECTORY/docbook-$1.cat.diff
}


mk_source_dir $SOURCE_DIRECTORY &&
dtd_src 4.5 '' &&
dtd_src 3.1 2  &&
dtd_src 4.3 3  &&
dtd_src 4.2 4  &&
dtd_src 4.4 5

.