Presentation at the Workshop on Open Finance and Participatory Budgeting. University of Bern, Haus der Universität Bern, Schlösslistrasse 5, Bern, Switzerland, 21 Jan 2015 http://www.iwi.unibe.ch/content/digitale_nachhaltigkeit/veranstaltungen/workshop_on_open_finance_and_participatory_budgeting/index_ger.html