 Classification of methanogenic bacteria by 16S ribosomal RNA characterization by George E. Fox and others

Primary source: doi.org/10.1073/pnas.74.10.4537

Verified locator: PNAS 74(10), 4537–4541 (October 1977). Primary Abstract pmc.ncbi.nlm.nih.gov/articles/PMC431980/ ; publisher indexed page 4537 pnas.org/doi/full/10.1073/pnas.74.10.4537 verifies full bylines and S_AB=2N_AB/(N_A+N_B), nucleotide-residue weighting for fragments at least six nucleotides.