Antiquarian Booksellers Association of America - http://www.abaa.org/

Celebrating more than 50 years of professional bookselling excellence.
The ABAA promotes ethical standards and professionalism in the antiquarian book trade, encourages the collecting and preservation of antiquarian books and related materials, supports educational programs and research into the study of antiquarian books, and facilitates collegial relations between booksellers, librarians, scholars, and collectors.

International League of Antiquarian Booksellers, ILAB - http://www.ilab-lila.com/

20 Nations and 2000 leading booksellers throughout the world dealing with fine and rare books, maps, prints & autographs.

The Western History Association - http://www.unm.edu/~wha/

An association that promotes the study of western North American history located on the campus of the University of New Mexico.

The Little Big Horn Associates, Inc.- http://www.lbha.org/

Information regarding the study of George A. Custer, Native Americans and the Indian Wars period.