 They constitute a comprehensive summary of the appended papers, and should clarify the contribution of the doctoral student if the papers are written by several authors.They should not provide new results, but may provide synthesis of new conclusions by combining results from several of the papers.They may supplement the articles with a motivation of the chosen scope, research problems, objectives and methods, and a strengthening of the theoretical framework, analysis and conclusions, since the extent of the articles normally does not allow this kind of longer discussions.