Wieriks, Koos; Schulte-Wülwer-Leidig, Anne (1997). "Integrated water management for the Rhine river basin, from pollution prevention to ecosystem improvement". Natural Resources Forum. 21 (2): 147–156. doi:10.1111/j.1477-8947.1997.tb00686.x. ISSN1477-8947.
handle.net
hdl.handle.net
Raith, Sarah (1999). "The Rhine Action Program: Restoring Value to the Rhine River". University of Minnesota, Department of Horticultural Science. hdl:11299/59277 – via University of Minnesota Digital Conservancy. {{cite journal}}: Cite journal requires |journal= (help)
Wieriks, Koos; Schulte-Wülwer-Leidig, Anne (1997). "Integrated water management for the Rhine river basin, from pollution prevention to ecosystem improvement". Natural Resources Forum. 21 (2): 147–156. doi:10.1111/j.1477-8947.1997.tb00686.x. ISSN1477-8947.