@article{Mulligan1972, 
     author = "Mulligan, Gordon D. and Corneil, D. G.", 
     doi = "10.1145/321694.321698", 
     issn = "00045411", 
     journal = "Journal of the ACM", 
     link = "http://portal.acm.org/citation.cfm?doid=321694.321698", 
     month = "apr", 
     number = "2", 
     pages = "244--247", 
     publisher = "ACM", 
     title = "Corrections to Bierstone's Algorithm for Generating Cliques", 
     uri = "http://portal.acm.org/citation.cfm?doid=321694.321698", 
     volume = "19", 
     year = "1972", 
}

Problems: 409