recommended reading on some weaponry

I'm looking into expanding on applications of some weapons I own. I have tried applying them to my Bujinkan training and meeting some results, but I'm wondering about looking into any other applications I may have missed.



1. Sai

2. Tonfa

3. Knife (single edge)

4. Nunchaku

5. Kusarigama (and any other weaponry)



I get that some of these are in kobudo, so are there any must have reads on the subject?