1. Research associate, Technical University of Munich, School of Management and School of Life Sciences Weihenstephan, Chair of Economics of Horticulture and Landscaping, Alte Akademie 16, 85354 Freising, Germany.
2. Professor, Technical University of Munich, School of Management and School of Life Sciences Weihenstephan, Chair of Economics of Horticulture and Landscaping, Alte Akademie 16, 85354 Freising, Germany.