A heuristic for the multiple tour maximum collection problem. - Steven E. Butt; Tom M. Cavalier (Comput. Oper. Res., 1994)

An optimal solution procedure for the multiple tour maximum collection problem using column generation. - Steven E. Butt; David M. Ryan (Comput. Oper. Res., 1999)

Modeling nurse-patient assignments considering patient acuity and travel distance metrics. - Ilgin Acar; Steven E. Butt (J. Biomed. Informatics, 2016)