Mineral Facts and Problems: 1960 Edition, report, 1960; (https://digital.library.unt.edu/ark:/67531/metadc38790/m1/36/: accessed April 25, 2024), University of North Texas Libraries, UNT Digital Library, digital.library.unt.edu; .
Mineral Facts and Problems: 1960 Edition, report, 1960; (https://digital.library.unt.edu/ark:/67531/metadc38790/m1/36/: accessed April 25, 2024), University of North Texas Libraries, UNT Digital Library, digital.library.unt.edu; .