@article{122190, recid = {122190}, author = {Kier, Porter M.}, title = {Upper Miocene echinoids from the Yorktown Formation of Virginia and their environmental significance}, publisher = {Smithsonian Institution Press; [for sale by the Supt. of Docs., U.S. Govt. Print. Off.]}, address = {Washington,}, pages = {41 p.}, year = {1972}, url = {http://library.usi.edu/record/122190}, }