The author would like to thank the following people for contributions, 
help and guidance regarding prodest:
  Leopoldo Catania <leopoldo.catania@uniroma2.it>
  Federico Tullio <federico_t@live.it>
  Leonardo M. Giuffrida <leonardo.giuffrida@uniroma2.it>
  Francesco Decarolis <francesco.decarolis@unibocconi.it>
