Guide to fossil collecting in Minnesota - Hoagberg, Rudolph K.; Sloan, Robert E. (Robert Evan) 1929-; Tufford, Sarah P. (Minneapolis University of Minnesota, Minnesota Geological Survey, 1967)
First ed. 1965, by Sarah Tufford and Rudolph Hogberg.
Bibliography: p. 29-30.
Keywords: Fossils -- Collection and preservation -- Minnesota