Some moths ago somebody here was looking for Polikarpov Po-2 (U-2)
operating/maintenance manual.
It's now available online, free of charge, page-by-page scanned from
original 1937 book.

See at http://twistairclub.narod.ru/u2/encontens.htm

Cheets,

MT
Russian General Aviation at http://twistairclub.narod.ru