1. Nonprotein amino acids in the Murchison meteorite;Kvenvolden,1971
2. Amino acids in the Murchison meteorite;Lawless;Geochim. Cosmochim. Acta,1973
3. Stereochemistry of amino acids;Neuberger,1948
4. Extraction of soil organic matter with anhydrous formic acid;Parsons,1960