The Congress shall have power to lay and collect taxes on incomes, from whatever source derived, without apportionment

The several state legislatures ratified the Sixteenth Amendment on the following dates: Alabama, August 10, 1909; Kentucky, February 8, 1910; South Carolina, February 19, 1910; Illinois, March 1, 1910; Mississippi, March 7, 1910; Oklahoma, March 10, 1910; Maryland, April 8, 1910; Georgia, August 3, 1910; Texas, August 16, 1910; Ohio, January 19, 1911; Idaho, January 20, 1911; Oregon, January 23, 1911; Washington, January 26, 1911; Montana, January 27, 1911; Indiana, January 30, 1911; California, January 31, 1911; Nevada, January 31, 1911; South Dakota, February 1, 1911; Nebraska, February 9, 1911; North Carolina, February 11, 1911; Colorado, February 15, 1911; North Dakota, February 17, 1911; Michigan, February 23, 1911; Iowa, February 24, 1911; Kansas, March 2, 1911; Missouri, March 16, 1911; Maine, March 31, 1911; Tennessee, April 7, 1911; Arkansas, April 22, 1911 (after having rejected the amendment at the session begun January 9, 1911); Wisconsin, May 16, 1911; New York, July 12, 1911; Arizona, April 3, 1912; Minnesota, June 11, 1912; Louisiana, June 28, 1912; West Virginia, January 31, 1913; Delaware, February 3, 1913; Wyoming, February 3, 1913; New Mexico, February 3, 1913; New Jersey, February 4, 1913; Vermont, February 19, 1913; Massachusetts, March 4, 1913; New Hampshire, March 7, 1913 (after having rejected the amendment on March 2, 1911). The amendment was rejected (and not subsequently ratified) by Connecticut, Rhode Island, and Utah.

http://www.gpoaccess.gov/constitution/html/conamt.html

A source would be nice, and since your account is a day old, you arent being given the benefit of the doubt.