"Ripley's Believe it or not" have just published a new book "Enter If You Dare".
I've checked and there's a good double page spread on flea circuses past and present with lots of photos and pictures. A nice "ask the expert" section covers the topic in detail.
It's available to buy now from the London Odditorium and I'm sure it will appear in bookshops soon too.
For more information, contact RipleyBooks