April 21 in history, these intelligence were sent to the US president

情报历史上的4月21日，这些情报被递交给时任美国总统

Intelligence History on 1962 April 21
Intelligence History on 1964 April 21
Intelligence History on 1965 April 21
Intelligence History on 1966 April 21
Intelligence History on 1967 April 21
Intelligence History on 1970 April 21
Intelligence History on 1971 April 21
Intelligence History on 1972 April 21
Intelligence History on 1973 April 21
Intelligence History on 1975 April 21
Intelligence History on 1976 April 21