@TechReport{economics.dp.2009-25,
 author = {Colombo, Stefano},
 title = {On the Effects of Selective Below-Cost Pricing in a Vertical Differentiation Model},
 type = {Economics Discussion Paper},
 institution = {Kiel Institute for the World Economy},
 year = {2009},
 number = {2009-25},
 url = {http://www.economics-ejournal.org/economics/discussionpapers/2009-25}
}