*O'Callaghan, Amy; van Sinderen, Douwe (2016). Bifidobacteria and Their Role as Members of the Human Gut Microbiota. Frontiers in Microbiology, 7, 
*Paul György; Robert F. Norris; Catharine S. Rose (1954). Bifidus factor. I. A variant of Lactobacillus bifidus requiring a special growth factor, 48 (1), 193–201.