For building osage selfbows, there is no better book than Dean Torges', Hunting the Osage Bow".

http://www.bowyersedge.com/books.html

Volume 1 of the Bowyer's Bibles is also a great start, though it's geared more towards selfbow making in general with less emphasis on bows specifically from osage.

That one can be found on-line at 3 Rivers Archery or Kustom King Archery.