Kenneth J Arrow, Levhari, David , and Sheshinski, Eytan . 1972. ?A Production Function For The Repairman Problem.?. http://search.ebscohost.com/login.aspx?direct=true&db=edsbas&AN=edsbas.fthighwire.oai.open.archive.highwire.org.restud.39.3.241&site=eds-live.