@article{derivatives,
 author = {Janusz A. Brzozowski},
 title = {Derivatives of Regular Expressions},
 journal = {J. ACM},
 volume = {11},
 number = {4},
 year = {1964},
 issn = {0004-5411},
 pages = {481--494},
 doi = {http://doi.acm.org/10.1145/321239.321249},
 publisher = {ACM Press},
 address = {New York, NY, USA},
 }