@TechReport{economics.dp.2009-10,
 author = {Kögel, Tomas},
 title = {On the Relation between Dual-Rate Discounting and Substitutability},
 type = {Economics Discussion Paper},
 institution = {Kiel Institute for the World Economy},
 year = {2009},
 number = {2009-10},
 url = {http://www.economics-ejournal.org/economics/discussionpapers/2009-10}
}