[Contribution to the study of Microphallidae (Trematoda). 51. Five species from the diver Gavia immer (Aves) of the United States, with Microphallus forresteri n. sp. A plurality resembling that of the species Microphallus nicolli (Cable & Hunninen, 1938).] Systematic Parasitology, 37(2), June 1997: 139-148. 140 [Zoological Record Volume 134]