A timeline which shows datasets from the Pressemappe 20 Jahrhundert Archive (http://webopac.hwwa.de/PresseMappe20/PM20.cfm?T=P&qt=155425&CFID=24875289&CFTOKEN=75756954). The datasets were fetched from wikidata. They all share the pm20 id and the position held head of state. (https://www.wikidata.org/wiki/Wikidata:WikiProject_20th_Century_Press_Archives/Use_cases#Heads_of_state)