I don't think you will find much about him he was a murmer in an ocean of talent, Compared with Capa, Alekhine, Steintz, Lasker who completly outclassed him. Why the interest in Janowski, there are better masters to study than him.
JANOWSKI MATTERS

Janowski was pretty good but i bet you would get your money's worth with other great players like Capa, Alekhine, Steintz, Lasker, Fischer and Kasparov, there games are probably way better and explain alot more then Janowski.. just my 1 cent.

http://www.chesshistory.com/winter/extra/janowsky.html
"The didactic value of Janowsky’s handling of the bishop pair was also stressed by Alekhine. Writing in 1945, he noted that the prodigy Arturo Pomar had not yet learned the value of the two bishops and advised that ‘it would be very profitable for him to study the best games of Janowsky’."
"...he was, for instance, the only master apart from Tarrasch to beat the first four world champions, Steinitz, Lasker, Capablanca and Alekhine. In all, he scored a dozen victories against them."
He is definitely worth study. A bit of trivia: He was the first GM opponent Reshevsky, age 11, beat in a tournament, in NY 1922.
Pic of this
http://www.chess.com/forum/view/general/greatest-chess-photos?page=18
though you can't see Janowski.
I also like that shot of Janowski from Winter's site.
Hello Im currently looking for books that are all about david janowski and articles about him on the internet anyone who knew him personally i could interview where he lived his favoerite movie (just kidding for the interview and that other stuff) I'd be most grateful im currently studying his games.