||Letarov A, Kulikov E. The bacteriophages in human- and animal body-associated microbial communities. J Appl Microbiol. 2009 Jul107(1):1-13. doi: 10.1111/j.1365-2672.2009.04143.x. p.6 left column top paragraphPubMed ID19239553
||Wiggins, B.A. and Alexander, M. (1985) Minimum bacterial density for bacteriophage replication: implications for significance of bacteriophages in natural ecosystems. Appl Environ Microbiol 48, 19–23.PubMed ID3156556
||P.6 left column top paragraph: "Coliform bacteria (>80% of them generally are E. coli) are normally present at 10^5–10^8 CFU/g in human and
animal faeces (BNID 112506). Streptococcus bovis is present at 10^6–10^7 CFU/ml of sheep rumenal fluid (BNID 112507). These cell densities are well above the reported threshold level of about 10^4cells/ml for exponential phage growth (primary source). Thus, some mechanisms stabilizing the coexistence of phages and their hosts have to be present."