Murray NE, Daniel AS, Cowan GM, Sharp PM (July 1993). "Conservation of motifs within the unusually variable polypeptide sequences of type I restriction and modification enzymes". Mol. Microbiol. 9 (1): 133–43. doi:10.1111/j.1365-2958.1993.tb01675.x. PMID8412658. S2CID45127462.
Murray NE, Daniel AS, Cowan GM, Sharp PM (July 1993). "Conservation of motifs within the unusually variable polypeptide sequences of type I restriction and modification enzymes". Mol. Microbiol. 9 (1): 133–43. doi:10.1111/j.1365-2958.1993.tb01675.x. PMID8412658. S2CID45127462.
Murray NE, Daniel AS, Cowan GM, Sharp PM (July 1993). "Conservation of motifs within the unusually variable polypeptide sequences of type I restriction and modification enzymes". Mol. Microbiol. 9 (1): 133–43. doi:10.1111/j.1365-2958.1993.tb01675.x. PMID8412658. S2CID45127462.