Encyclopedia of associations : a guide to approximately 20,000 national and international organizations including: trade, business, and commercial ; agricultural and commodity ; legal, governmental, public administration, and military ; scientific, engineering, and technical ; educational ; cultural ; social welfare ; health and medical ; public affairs ; fraternal, foreign interest, nationality, and ethnic ; religious ; veteran, hereditary, and patriotic ; hobby and avocational ; athletic and sports ; labor unions, associations, and federations ; chambers of commerce ; and Greek letter and related organizations /