Kowalchuk, G. A., Stephen, J. R., De Boer, W., Prosser, J. I., Embley, T. M., & Woldendorp, J. W. (1997). Analysis of ammonia-oxidizing bacteria of the beta subdivision of the class Proteobacteria in coastal sand dunes by denaturing gradient gel electrophoresis and sequencing of PCR-amplified 16S ribosomal DNA fragments.

Kowalchuk, G A., J R. Stephen, W. De Boer, J I. Prosser, T M. Embley, and J W. Woldendorp. Analysis of Ammonia-oxidizing Bacteria of the Beta Subdivision of the Class Proteobacteria in Coastal Sand Dunes By Denaturing Gradient Gel Electrophoresis and Sequencing of PCR-amplified 16S Ribosomal DNA Fragments. 1997.

Kowalchuk, G A., et al. Analysis of Ammonia-oxidizing Bacteria of the Beta Subdivision of the Class Proteobacteria in Coastal Sand Dunes By Denaturing Gradient Gel Electrophoresis and Sequencing of PCR-amplified 16S Ribosomal DNA Fragments. 1997.