attempts by the Holy Roman Empire, including several over the centuries by the Emperor, to regulate toll collection on the Rhine failed. And it was not until the establishment of the "Rhine League" of the Emperor with certain nobles and clergy that the "Robber barons" control over the Rhine was crushed. River tolls on the Rhine, increasingly imposed by states rather than individual lords, remained a sticking point in relations and commerce in the Rhine basin until the establishment of the Central Commission for Navigation on the Rhine in 1815. Heller and Rebecca S. Eisenberg are academic law professors who believe that biological patents create a "tragedy of the anticommons", "in which people underuse scarce resources because too many owners can block each other." Others claim that patents have not created this "anticommons" effect on research, based on surveys of scientists. See also References Further reading Rose, Carol M. (1986) The Comedy of the Commons: Commerce, Custom and Inherently Public Property, 53 University of Chicago Law Review 711, reprinted as chapter 5 in: Rose, Carol M., Property and persuasion: Essays on the history, theory and rhetoric of ownership, Westview Press 1994 External links Heller's talk in the Authors@Google series Anticommons Game theory Market failure Property Public commons