The Treaty of Versailles in the mind of the Germans stabbed them in the back, especially the guilt clause that made them take blame for the First World War. Hitler capaitalized on these sentiments and used them to rally the German people.
Primary sources are the first hand evidence left behind by participants or observers at the time of events. Primary sources originate in the time period that historians are studying. They vary a great deal.
Tertiary Sources. Tertiary sources are the furthest removed from the origin of an event, idea, or period. While secondary sources are the interpretation and evaluation of primary sources, tertiary sources are essentially summaries or collections of primary and/or secondary sources. In simple terms, tertiary sources distill primary and secondary sources into a format that is accessible to a general audience.