DeWalle, F. B., Nikolopoulou-Tamvakli, M., Heinen, W. J., DeWalle, F. B., Nikolopoulou-Tamvakli, M., DeWalle, F. B., . . . Silano, V. (1993). Environmental condition of the Mediterranean Sea: European Community countries. Dordrecht: Kluwer Academic Publishers.

DeWalle, Foppe B., M. Nikolopoulou-Tamvakli, W. J. Heinen, Foppe B. DeWalle, M. Nikolopoulou-Tamvakli, F. B. DeWalle, Μ Νικολοπούλου-Ταμβακλή, W. J. Heinen, and V. Silano. Environmental Condition of the Mediterranean Sea: European Community Countries. Dordrecht: Kluwer Academic Publishers, 1993.

DeWalle, Foppe B., et al. Environmental Condition of the Mediterranean Sea: European Community Countries. Dordrecht: Kluwer Academic Publishers, 1993.