Source: http://www.chanrobles.com/usa/us_supremecourt/constitution/amendment-20/index.php
Timestamp: 2019-04-24 19:57:20+00:00

Document:
As thus stated, the exact term of the President and Vice President was fixed by the Constitution, Art. II, § 1, cl. 1, at 4 years, and became actually effective, by resolution of the Continental Congress, on the 4th of March 1789. Since this amendment was declared adopted on February 6, 1933, § 1 in effect shortened, by the interval between January 20 and March 4, 1937, the terms of the President and Vice President elected in 1932.
Similarly, it shortened, by the intervals between January 3 and March 4, the terms of Senators elected for terms ending March 4, 1935, 1937, and 1939; and thus temporarily modified the Seventeenth Amendment, fixing the terms of Senators at 6 years. It also shortened the terms of Representatives elected to the Seventy-third Congress, by the interval between January 3 and March 4, 1935, and temporarily modified Article I, § 2, clause 1, fixing the terms of Representatives at 2 years.
1 S. Rep. No. 26, 72d Cong., 1st Sess., 2, 4, 5, 6 (1932).
Section 1 further modifies the Twelfth Amendment in its reference to March 4 as the date by which the House must exercise its choice of a President.
Pursuant to the authority conferred upon it by § 3 of this amendment, Congress shaped the Presidential Succession Act of 19485 to meet the situation which would arise from the failure of both President elect and Vice President elect to qualify on or before the time fixed for the beginning of the new Presidential term.
2 Ch. 10, 14 Stat. 378.
3 Ch. 21, § 30, 17 Stat. 12. See 1 A. HINDS' PRECEDENTS OF THE HOUSE OF REPRESENTATIVES § 11 (1907).
4 Ch. 713, 49 Stat. 1826.

References: § 1
 § 1
 § 2
 § 3
 § 30
 § 11