The term "reliability-centered maintenance" authored by Tom Matteson, Stanley Nowlan and Howard Heap of United Airlines (UAL) to describe a process used to determine the optimum maintenance requirements for aircraft (having left United Airlines to pursue a consulting career a few months before the publication of the final Nowlan-Heap report, Matteson received no authorial credit for the work). The US Department of Defense (DOD) sponsored the authoring of both a textbook (by UAL) and an evaluation report (by Rand Corporation) on Reliability-Centered Maintenance, both published in 1978. They brought RCM concepts to the attention of a wider audience.