The occurrence of porcelaneous datolite in Michigan's lake Superior Copper district - part 2: southern Keweenaw, Houghton, and Ontonagon counties, Michigan
Rosemeyer Tom, The occurrence of porcelaneous datolite in Michigan's lake Superior Copper district - part 2: southern Keweenaw, Houghton, and Ontonagon counties, Michigan, Rocks and minerals , 80(3), 2005, pp. 154-177