Some useful resources for saw doctors, makers and restorers 

Enhancing the Handsaw Etch by Bob Sturgeon

Saw Blade and Nib Restoration by James D. Thompson

Straightening Saws - Scientific American, 1877

Straightening Bent Handsaw Blades

Concerning hang angles and saw handles — Blackburn Tools

The Backsaw Project — Norse Woodsmith

Building two saws — The Literary Workshop Blog

 How to Make Handsaws — instructables.com