Gases that Occur in Metal Mines, report, 1931; (https://digital.library.unt.edu/ark:/67531/metadc12517/m1/1/: accessed May 12, 2024), University of North Texas Libraries, UNT Digital Library, digital.library.unt.edu; .
Gases that Occur in Metal Mines, report, 1931; (https://digital.library.unt.edu/ark:/67531/metadc12517/m1/1/: accessed May 12, 2024), University of North Texas Libraries, UNT Digital Library, digital.library.unt.edu; .