Form RE [http://www.loc.gov/copyright/forms/formrei.pdf]

for claims to renew copyright in works copyrighted under the law in
effect through December 31, 1977 (1909 Copyright Act) and registered
during the initial 28-year copyright term

Form RE Addendum [http://www.loc.gov/copyright/forms/formrea.pdf]

accompanies Form RE for claims to renew copyright in works copyrighted
under the 1909 Copyright Act but never registered during their initial
28-year copyright term


***
For Corrections and Amplifications

Form CA [http://www.loc.gov/copyright/forms/formca.pdf]

for supplementary registration to correct or amplify information given
in the Copyright Office record of an earlier registration


***
For a Group of Contributions to Periodicals

Form GR/CP [http://www.loc.gov/copyright/forms/formgrcp.pdf]

an adjunct application to be used for registration of a group of
contributions to periodicals in addition to an application Form TX,
PA, or VA