Provisional "Bangaldesh" overprints on Pakistan

Hi,

I have some Pakistan stamps, overprinted with "Bangladesh" in different
types. I know, that they were issued in 1971 after independence of
Bangladesh. Do you know an internet address, where are these stamps
listed, with pictures, that I can separate the different types. Maybe I
can find in which cities these stamps were issued. I tried Google, but
did not find a good homepage.

Best wishes from Germany
Manuel )