There are several international documents defining requirements for e-voting (enlisted in alphabetical order of the issuing body) and that are aimed at supporting national Electoral Management Bodies with the development and implementation of e-voting projects:

Council of Europe

• The Council of Europe Recommendation [Recommendation Rec(2004)11 of the Committee of Ministers to member states on legal, operational and technical standards for e-voting, adopted by the Committee of Ministers on 30 September 2004 at the 898th meeting of the Ministers' Deputies; https://wcd.coe.int/ViewDoc.jsp?id=778189] specifies detailed requirements for using electronic means in elections. It comprises 121 requirements that serve as a checklist for implementing e-voting. The Council of Europe Recommendation is supposed to be reviewed and revised in the near future.
• In 2010 the Directorate General of Democracy and Political Affairs of the Council of Europe published two Guidelines that took account of developments after the adoption of the Rec(2004)11: Guidelines on transparency of e-enabled elections [GGIS(2010)5]; http://www.coe.int/t/dgap/democracy/activities/ggis/E-voting/E-voting%202010/Biennial_Nov_meeting/Guidelines_transparency_EN.pdf and Certification of e-voting systems: Guidelines for developing processes that confirm compliance with prescribed requirements and standards [GGIS(2010)3]; http://www.coe.int/t/dgap/democracy/activities/ggis/e-voting/E-voting%202010/Biennial_Nov_meeting/Guidelines_certification_EN.pdf.
• Additionally, in 2010, the Directorate General of Democracy and Political Affaires also published a handbook on e-voting: E-Voting Handbook - Key Steps in the Implementation of E-Enabled Elections; http://www.coe.int/t/DEMOCRACY/ELECTORAL-ASSISTANCE/themes/evoting/CoEvotingHandbook_en.pdf. The handbook reflects the findings of e-voting experiments held in European countries.

International IDEA

• In December 2011, International IDEA issued a Policy Paper “Introducing Electronic Voting: Essential Considerations” that contains guiding principles and overall goals for the implementation of e-voting; http://www.idea.int/publications/introducing-electronic-voting
• In 2014, International IDEA published a Guide on “The Use of Open Source Technology in Elections” which is aimed at enhancing the understanding of Open Source Technology among key electoral stakeholders; http://www.idea.int/publications/open-source-technology-in-elections/index.cfm

Several international documents focus on new technologies and election observation:

• The Carter Center Handbook on Observing Electronic Voting (2^nd edition, January 2012); http://www.cartercenter.org/resources/pdfs/peace/democracy/des/Carter-Center-E_voting-Handbook.pdf
• The Carter Center, Developing a Methodology For Observing Electronic Voting (October 2007); http://www.needsproject.eu/files/developing_methodology_observing_e_voting.pdf
• Jordi Barrat, Observing E-Enabled Elections: How to Implement Regional Electoral Standards, International IDEA (2012); http://www.idea.int/democracydialog/upload/Observing-e-enabled-elections-how-to-implement-regional-electoral-standards.pdf
• European Commission, Handbook for European Union Election Observation, Second Edition (2008); http://eeas.europa.eu/eueom/pdf/handbook-eueom-en-2nd-edition_en.pdf
• The Organization of American States (2010); http://www.oas.org/es/sap/docs/Technology%20English-FINAL-4-27-10.pdf
• OSCE/ODIHR, Handbook for the Observation of New Voting Technologies (October 2013); http://www.osce.org/odihr/elections/104939

Further international documents are aimed at assisting EMBs in dealing with e-voting, e.g.

• The ACE Project topic area “Elections and Technology” contains comments on e-voting; https://aceproject.org/ace-en/topics/et/default
• Ben Goldsmith/Holly Ruthauff: Implementing and Overseeing Electronic Voting and Counting Technologies. A study resulting from a close collaboration between the International Foundation for Electoral Systems (IFES) and the National Democratic Institute (NDI), supported by the United States Agency for International Development (USAID); http://www.ifes.org/Content/Publications/Books/2013/Implementing-and-Overseeing-Electronic-Voting-and-Counting-Technologies.aspx