. . "Geological Survey (U.S.)," . . "Shale." . . . "Element distribution in some trough and platform types of black shale and associated rocks"@en . . "Element distribution in some trough and platform types of black shale and associated rocks : the content and association of minor elements in different black shale environments" . . . . . . . . . . . . "The content and association of minor elements in different black shale environments."@en . "Element Distribution in Some Trough and Platform Types of Black Shale and Associated Rocks : Contributions to Geochemistry" . . . . . "Shale United States." . . "United States." . .