Era
1945-
3
1985-1991
2
1986-1991
2
1990
2
20th century
2
Cases
2
1804-1881
1
1809-1898
1
1837-1901
1
1871-1918
1
1918-1945
1
1919-1947
1
1945-1962
1
1960-1980
1
19th century
1
20th Century
1
20th century --
1
Japan
1
Modern period, 1600-
1
Problems, exercises, etc
1
Revolution, 1954-1962
1
South Pacific region
1