SIRC Sport Research (http://www.sirc.ca/index.cfm) is a not-for-profit organization based in Ottawa Canada. Founded in 1973 as a resource for coaches, athletes, sports medicine professionals and sporting organizations, SIRC is a leading source for academic and medical sport research.
The American Soccer History Archives (http://www.sover.net/~spectrum/) are a comprehensive repository of information, statistics and essays relating to all aspects of the history of soccer in the United States from the 1860's to the present.