Thanks to all who responded. The correct citation is: Donges, J. 1970. Transplantation of rediae - a device for solving special problems in trematodology. [Abstract]. J. Parasit. 56(4, Sect.2)(Int. Congr. Parasit. (2nd), Washington DC, Sept. 6-12, 1970, Proceedings, Part I), pp.82-83. Thanks again for the help, Derek Zelmer