Hartmann published his dissertation in 1976, titled The American President in the related field of Congress fractions: Structures, strategies and implementation problems in the relations of Presidents Kennedy, Johnson and Nixon to majority groups in Congress (1961-1973).
[1] In 1982, he wrote "Political profiles of Western European industrial society" habilitation.
His publications deal largely with international and governmental systems of various kinds, mainly in the western hemisphere.
[3] In addition, he worked intensively with the History of Political Science in European-American comparison study, his case is based on the US scale.
[4] However, the reduction in the history of the German political science in the period after 1945 by Wilhelm Bleek contained therein as "problematic "in [5]