[1] Univ Illinois, Univ Illinois, One Univ Plaza, Springfield, IL 62703 USA
[2] Justus Liebig Univ Giessen, Prof Versorgungs & Verbrauchsforsch FB09, Senckenbergstr, Giessen, Germany
[3] Copenhagen Business Sch, Sustainable Consumpt, Frederiksberg, Denmark
[4] Univ Nebraska, Mkt, Lincoln, NE USA