Book Review: The Costanzo Obligation The obligations of national administrative authorities in the case of incompatibility between national law and European law, by Maartje Verhoeven. (A - Common Market Law Review View Book Review: The Costanzo Obligation The obligations of national administrative authorities in the case of incompatibility between national law and European law, by Maartje Verhoeven. (A by - Common Market Law Review Book Review: The Costanzo Obligation The obligations of national administrative authorities in the case of incompatibility between national law and European law, by Maartje Verhoeven. (A 49 4 Common Market Law Review