TWG predecessors and rivals
From WorldGovWiki
Davis, 1953
World Government of World Citizens: http://www.worldgovernment.org/
Isely - Martin, 1958
World Constitution and Parliament Association (1958-): http://www.radford.edu/gmartin/WCPA%20page.htm
Earth Federation Movement: http://earthfederation.info/
World Constitutional Convention / World Constituent Assembly (1968, 1972, 1979)
The Constitution for the Federation of Earth: http://www.radford.edu/gmartin/CEF.pdf
Provisional World Parliament (13 sessions, 1982-2012; 14th scheduled Dec.2015): http://worldparliament-gov.org/
List of World Legislative Act: http://www.radford.edu/gmartin/PWP.legis.acts.list.htm
Stark - Stalets, 2004
Vote World Parliament: http://voteworldparliament.org/