Era
1945-
51
20th century
30
1945-1989
14
1989-
12
21st century
10
1947-
9
history
9
19th century
8
20th century. --
8
1979-1997
6
1985-1991
6
1989-1993
6
1979-
5
1925-
4
1945-1991
4
1976-2000
4
1990-
4
1945 --
3
1949-
3
1951-
3
1966-1998
3
1975-
3
1981-1989
3
1991-
3
1993-2001
3
Congresses
3
1868-
2
18th century
2
1945
2
1959-
2
1964-
2
1964-1979
2
1965-1975
2
1971-
2
1975-1985
2
1976-
2
1976-2002
2
1998-
2
20th century --
2
Islam
2
history --
2
1
(11th:1979:Moscow, R.S.F.S.R.}
1
1689-1702
1
1714-1830
1
1767-1845
1
1786-1844
1
1889-1945
1
1902-
1
1904-
1
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