The best sourse that I can think of, off the top of my head is a book called "The Dance" by a guy named Brad Henderson. It's very popular. A few years ago, I wanted a copy of it, but found out it was out of print. I contacted every magic shop I could think of to see if they had a copy on the shelf. No luck. I even called Brad at home and asked him if HE had an extra copy lying around. He didn't, but he did say that he was considering a paperback release within the next year.
Finally, a second printing WAS released and they have now disappeared as well. Your dealer can special order it. I HIGHLY recommend it. It's worth every penny.
Murphy's Magic shows they have 28 copies left. Have your local dealer order you one.
Here's the description for it.....
The Dance
by Brad Henderson
Quickly selling out in its first edition, THE DANCE is now recognized as one of the most important books written on the subject of cold reading. Revealed, often for the first time, are the the tricks of the trade employed by psychics to convince the public they are delivering profound messages replete with specific details. THE DANCE will teach you both what to do and how to do it, including:

Asking the right questions

Your natural safety net

Handling skeptics

Dealing with stereotypes

Spinning a miss into a hit

Getting them to do the work

Ethical Issues

Avoiding common mistakes

Rewriting their memory

Readings from the stage.
Finally,
THE DANCE closes with two audience-tested performance pieces that will allow you to develop your cold reading skills while entertaining your audience.
98 pages, paperback