The texts of treaties are generally available from the sponsoring organisation, government web sites, or specialist research sources.
European Treaties under the auspices of the Council of Europe
http://conventions.coe.int/Treaty/Commun/ListeTraites.asp?CM=8&CL=ENG
Humanitarian treaties under the auspices of the Red Cross
www.icrc.org/ihl
United Nations Charter
www.un.org/aboutun/charter/
Convention on the Law of the Sea 1982
www.un.org/Depts/los/convention_agreements/convention_overview_convention.htm
Resolutions of the Security Council
www.un.org/Docs/sc/unsc_resolutions.html