Salton, Milton R. J.; Kim, Kwang-Shin (1996), Baron, Samuel (ed.), "Structure", Medical Microbiology (4th ed.), University of Texas Medical Branch at Galveston, ISBN978-0-9631172-1-2, PMID21413343, retrieved 2020-05-16
Salton, Milton R. J.; Kim, Kwang-Shin (1996), Baron, Samuel (ed.), "Structure", Medical Microbiology (4th ed.), University of Texas Medical Branch at Galveston, ISBN978-0-9631172-1-2, PMID21413343, retrieved 2020-05-16