Otsuka AJ, Buoncristiani MR, Howard PK, Flamm J, Johnson C, Yamamoto R, Uchida K, Cook C, Ruppert J, Matsuzaki J (December 1988). "The Escherichia coli biotin biosynthetic enzyme sequences predicted from the nucleotide sequence of the bio operon". The Journal of Biological Chemistry. 263 (36): 19577–85. PMID3058702.