1. Comparison of atmospheric methane content above Flagstaff, Arizona and Columbus, Ohio;Adel;Phys. Rev.,1949
2. Natural sources of gaseous pollutants in the atmosphere;Altshuller;Tellus,1958
3. Studies upon the methane-producing bacteria;Barker;Arch. f. Mikrobioi.,1936
4. Biological formation of methane;Barker;Ind. Eng. Chem.,1956
5. Denitrification in soil (I). Method of investigation;Bremner;J. Agr. Sci.,1958