Table schema:
CREATE TABLE table_name_90 (year VARCHAR, nation_of_citizenship VARCHAR, type_of_vehicle VARCHAR, racing_series VARCHAR)

Question: What year has the vehicle of open wheel and a racing series of formula one with a Nation of citizenship in Germany.
SQL: SELECT year FROM table_name_90 WHERE type_of_vehicle = "open wheel" AND racing_series = "formula one" AND nation_of_citizenship = "germany"