Keep up the good work, guys.
Try and get a hold of the Archive book that was published in 2008. It has lots of background information as well as bonus chapters from the original manga that weren't published with the original compilation.
https://tinyurl.com/y785vk2z
https://www.ebay.com/itm/JAPAN-Birdy-the-Mighty-Tetsuwan-Birdy-Archive-Masami-Yuki/173594563868?hash=item286b0ad51c:g:j3MAAOSwpkFY8SxS
https://tinyurl.com/y97cbzv3
https://tinyurl.com/yd2u2mbb