qnli question: Which agreement was signed in 1954 by writers, linguists, and literary critics? sentence: In 1954, major Serbian and Croatian writers, linguists and literary critics, backed by Matica srpska and Matica hrvatska signed the Novi Sad Agreement, which in its first conclusion stated: "Serbs, Croats and Montenegrins share a single language with two equal variants that have developed around Zagreb (western) and Belgrade (eastern)".