A Zidane clustering theorem : why top players tend to play in one team and how the competitive balance can be restored Vöpel, Henning 2013 - HWWI EPflicht - frei zugänglich
Is Financial Fair Play really justified? : an economic and legal assessment of UEFA's Financial Fair Play rules Vöpel, Henning 2013 - HWWI EPflicht - frei zugänglich