Collinson, C. W. S. Field Book: Pennsylvanian Plant Fossils of Illinois.
Cita Chicago Style (17a ed.)Collinson, Charles William; Skartvedt. Field Book: Pennsylvanian Plant Fossils of Illinois.
Cita MLA (9a ed.)Collinson, Charles William; Skartvedt. Field Book: Pennsylvanian Plant Fossils of Illinois.
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