Operational research in the field practice area.

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. This record was last updated on 06/14/2016 and may not reflect the most current and accurate biomedical/scientific data available from NLM. The corresponding record at NLM can be accessed at https://www.ncbi.nlm.nih.gov/pubmed/4802555