United States Senate
https://www.senate.gov/artandhistory/history/resources/pdf/SPrt99-87.pdf
United States Government Printing Office
https://www.gpo.gov/fdsys/pkg/GPO-CONAN-1992/pdf/GPO-CONAN-1992-7.pdf
The Constitution has been amended on various occasions since its adoption. Although there are several ways to adopt an amendment, the only one utilized so far is where Congress proposes an amendment (by a two-thirds vote in each house), and for three- fourths of the states to adopt it in order to become law.
This process generates documents in the congressional stage, including the typical legislative history documents such as committee reports, hearings, and debate. All of this material can be researched using the standard research sources (with consideration for the dates of the material and generally availability of documents.) For more information on the amendment process, see page at the National Archives site (http://www.archives.gov/federal-register/constitution/). Congressional documents and debate are available online at institutions with a full subscription to the ProQuest Congressional database. Sites on the Internet may offer some collections of legislative history related to individual amendments. For example, the Library of Congress offers a bibliography and related materials on the 14th Amendment at http://www.loc.gov/rr/program/bib/ourdocs/14thamendment.html.