Maintenance work on the ZORA database servers is scheduled for Thursday 25th July 2019 from 19:00-20:00. During this period ZORA and JDB will not be available. Thank you for your understanding.
Ludwig, Markus (2015). Robust estimation of shape-constrained state price density surfaces. The Journal of Derivatives, 22(3):56-72.
Ludwig, Markus. Three Essays on Option Implied Information. 2015, University of Zurich, Faculty of Economics.