De vierde macht revisited, [Oratie]. 2000. Universiteit Utrecht. Analysing and Assessing Accountability: A Conceptual Framework (2007). European Law Journal, 13(4),447-468. Does Public Accountability Work? An Assessment Tool, met T. Schillemans en P. ’t Hart, (2008). Public Administration, 86(1), 225-242. Two Concepts of Accountability: Accountability as a Virtue and as a Mechanism, (2010). West European Politics, 33(5), 946-967. Indexing Watchdog accountability powers: a framework for assessing the accountability capacity of independent oversight institutions, (2021). Regulation and Governance, 2021(15), 856-876.