What are some significant dates related to the implementation of the mentioned constitutional amendments?
1. The Constitution (Forty-fourth Amendment) Act, 1978: Implemented on June 20, 1979
2. The sub-heading "Right to Property" was omitted by the Constitution (Forty-second Amendment) Act, 1976, and came into effect on January 3, 1977.
3. The Constitution (First Amendment) Act, 1951: Implemented with retrospective effect.
4. The Constitution (Fourth Amendment) Act, 1955: Substituted clause (1) with retrospective effect.