Does anybody know how TRAP staining works?

[daylily]

Tartrate resistant acid phosphatase staining of osteoclasts
I've done it, but I don't know how it works exactly.
I just couldn't google anything about this.
I need to prepare the answer for an oral exam.
Please help me out.
Thanks.

[MichaelXY]

I am not sure if this is helpful to you, but try.

http://www.jhc.org/cgi/content/abstract/48/2/219