1. A new avian fossil from Kern County, California.;H Howard;Condor,1969
2. Hikoshima specimens from the Orio Sandstone Bed, Shimonoseki City, Yamaguchi Prefecture, part V,;Y Hasegawa;Preliminary notes on the Oligo-Miocene penguin-like birds from Japan. Kitakyushu Museum of Natural History Bulletin,1979
3. Fossil counterparts of giant penguins from the North Pacific.;SL Olson;Science,1979
4. A new genus of penguin-like pelecaniform bird from the Oligocene of Washington (Pelecaniformes: Plotopteridae).;SL Olson;Natural History Museum of Los Angeles County, Contributions in Science,1980
5. A femur of Plotopterum from the early Middle Miocene of Japan (Pelecaniformes: Plotopteridae).;SL Olson;National Science Museum Tokyo Bulletin Series C,1985