	Authors	Year	Title
	Bogoslovskaya	1990	Osnovye puti razvitiya i klassifikatsiya pozdnepaleozoyskikh ammonoidey Marathonitaceae i Cyclolobaceae. Trudy Paleontologicheskogo Instituta Akademiya Nauk SSSR, 243: 70-86, fig.1-3; Moskva.
	Liang	1981	Early Permian cephalopods from Northwestern Gansu and Western Nei Monggol. Acta Paleontologica Sinica, 20 (6): 485-500, fig.1-12, pl.1-3; Beijing.