Varieties - kostenloses Unterrichtsmaterial, Arbeitsblätter und Übungen
Varieties of Democracy (V-Dem)
The international research project aims ʺto produce new indicators of democracy for all countries since 1900.ʺ Der V-Dem Liberal Democracy Index (LDI) bildet das Niveau der liberalen Demokratie in der Welt ab (University of Gothenburg Sweden 2020)
List of electoral systems by country
Wikipedia explains the various electoral systems (2018)