The term CULBERTSON refers to the American bridge player and writer, Ely Culbertson (ELY), who was a pioneer in the game of contract bridge. He wrote several books on the subject, including 'Contract Bridge Blue Book' (ELYS). He was also known for his rivalry with Charles Goren (GOREN), who developed the point-count system for bidding. Culbertson is also credited with inventing the SLAM bidding convention (SLAM).