Stephen Hart wrote in 2007 that post-war memoirs by Allied generals led to disputes along national lines during the 1950s and 1960s, with American historians generally critical of Montgomery and the actions of the Anglo-Canadian forces, while "pro-Montgomery" historians set out to refute them. Also published during this period were the national official campaign histories, which were thoroughly-researched but avoided detailed critical analysis of the controversies. During the 1980s, revisionist writers concentrated on the perceived deficiencies of the Allies and since the late 1990s, two schools of thought have been revising the revisionists, some expanding on revisionist work by providing a more detailed campaign analysis and those who have tried to show that the techniques employed by the Anglo-Canadian forces were realistic for the circumstances encountered Normandy.