US Department of Labor, Oil and Gas Well Drilling and Servicing eTool: Glossary of Terms (an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin, Occupational Safety & Health Administration OSHA, Washington, D.C., USA 2001, https://www.osha.gov/SLTC/etools/oilandgas/glossar y_of_terms/glossary_of_terms_a.htm, (OSHA/ Oil and Gas - Amer) {617}