Something like in the title, recent books are also acceptable but Im more interested in actual sources and way of thinkingn of creators of the art.
I've already read gorin no shō, by Musashi, and I also train in old japanese martial arts so these sources will be very benefficial for me but I just dont know where to look for to find authentic sources. I dont want books written for modern businessmen etc.
by WiesiekZdobywca