Based on the clue 'between negative 576 positive 576 its the last in...', what is the answer?

What is associated with: between march 1 1781 march 4 1789 when the constitution came into effect the government was ru… Based on the clue 'between may july this man a small crew crossed t...', what is the answer? What is associated with: between may 1965 march 1967 he defended his heavyweight boxing title an amazing 9 times? Based on the clue 'between meals meal can linner be far behind', what is the answer? Based on the clue 'between new hampshire vermont runs this river nam...', what is the answer? Based on the clue 'between new zealands north island south island', what is the answer? Based on the clue 'between obstetrician pediatrician comes this spec...', what is the answer? What is associated with: between oct 1946 oct 1949 this international organization held its meetings in flushing ny?