The best source on the Zero's development that I have found is Robert
Mikesh, Zero: Japan's Legendary Fighter. You can get it at Historic
Aviation: http://tinyurl.com/uobs

all the best -- Dan Ford
email: (put CUB in subject line)

see the Warbird's Forum at www.warbirdforum.com
and the Piper Cub Forum at www.pipercubforum.com