found: Visegrad drama, 2002- :p. 8 (Visegrad group; consists of Czech Republic, Hungary, Poland, and Slovak Republic; founded Feb. 15, 1991)
found: Visegrád Group WWW home page, Dec. 4, 2003:(Visegrád Group; Visegrad Four; V4; V4 Group; originally called Visegrad Troika; "Four" resulted from 1993 split of Czechoslovakia into Czech Republic and Slovakia)
found: Wikipedia WWW home page, Dec. 4, 2003:(Visegrad group; Visegrad 4; V4)
found: LC database, Dec 4, 2003:(variant: Grupa Wyszehradzka)
found: Visegrad States between Schengen and neighbourhood, 2005.