Operations, Psychological (Military science) -- See Psychological warfare Here are entered general works dealing with methods used to undermine the morale of the civilian population and the military forces of an enemy country. --subdivision Psychological aspects under names of wars, e.g. World War, 1939-1945--Psychological aspects
Operations, Undercover (Espionage) -- See Espionage
--subdivision Secret service under names of wars, etc., e.g. World War, 1939-1945--Secret service; United States--History--Civil War, 1861-1865--Secret service
Operative dentistry -- See Dentistry, Operative Here are entered works on that field of dentistry concerned with restoring diseased or defective teeth to a state of normal function, health and aesthetics.
Operative obstetrics -- See Obstetrics Surgery Here are entered works on obstetrical operations. Works on non-obstetrical operations performed on pregnant women are entered under Pregnant women--Surgery.
Operative surgery -- See Surgery, Operative Here are entered works dealing with the details of surgical operations. Literature relating to the risks and accidents of operations, treatment of patients after operations, and other generalities are entered under the heading Operations, Surgical. Works relating especially to methods of securing asepsis are entered under Surgery, Aseptic and antiseptic. --subdivision Surgery under names of organs and regions of the body and under names of diseases, e.g. Heart--Surgery; Foot--Surgery; Cancer--Surgery