Benny Morris, based on these newly released documents, and his influence on the debate, concluding that, whilst such Zionist writers add to the traditional understanding of the Palestinian exodus, their arguments do not disprove Morris' multi-causal explanation. Criticism of traditional positions Glazer also says, "Israeli public opinion has maintained that as the Arabs planned to massacre the Jews, when the Jews began winning the war the Arabs fled, fearing the same treatment would be suffered on them." Globally, in his paper of 1981, Glazer wrote, "Both Palestinians and Israeli spokesmen and adherents have sought to link the events of 1948 with their claims to the land today." He claims that one "fundamental [problem of the subject is to deal] with historians who are overtly biased" and try to identify the factors that influence this. Opening of archives In the 1980s Israel and United Kingdom opened up part of their archives for investigation by historians. This favored a more critical and factual analysis of the 1948 events. As a result more detailed and comprehensive description of the Palestinian exodus was published, notably Morris' The Birth of the Palestinian Refugee Problem. Morris distinguishes four waves of refugees, the second, third and fourth of them coinciding with Israeli military offensives, when Arab Palestinians fled the fighting, were frightened away, or were expelled. A document produced by the Israeli Defence Forces Intelligence Service entitled "The Emigration of the Arabs of Palestine in the Period 1/12/1947 – 1/6/1948" was dated 30 June 1948 and became widely known around 1985. The document details 11 factors which caused the exodus, and lists them "in order of importance": Direct, hostile Jewish [ Haganah/IDF ] operations against Arab settlements. The effect of our [Haganah/IDF] hostile operations against nearby [Arab] settlements... (... especially the fall of large neighbouring centers). Operation of [Jewish] dissidents [ Irgun Tzvai Leumi and Lohamei Herut Yisrael] Orders and decrees by Arab institutions and gangs [irregulars]. Jewish whispering operations [psychological warfare], aimed at frightening away Arab inhabitants. Ultimate expulsion orders [by Jewish forces] Fear of Jewish [retaliatory] response [following] major Arab attack on Jews. The appearance of gangs [irregular Arab forces] and non-local fighters in the vicinity of a village. Fear of Arab invasion and its consequences [mainly near the borders]. Isolated Arab villages in purely [predominantly] Jewish areas. Various local factors and general fear of the future. According to Shay Hazkani, "In the past two