1. "Top Monotonicity: a Common Root for Single Peakedness, Single Crossing and the Median Voter Result", (joint with B. Moreno), WP297 CREA-Barcelona Economics, 2007.Revised 2008.

2. "Free Triples, Large Indifference Classes and the Majority Rule", (joint with Lars Ehlers), WP512.02 UAB-CSIC and WP15 CREA-Barcelona Economics, 2002. Revised 2008.