Signals Intelligence -- See Electronic surveillance Here are entered general works on the monitoring of events from remote or secret locations by electronic means in the fields of law enforcement, criminal investigation, espionage, remote sensing for scientific purposes, etc.
Signets -- See Seals (Numismatics) Here are entered works on devices, such as emblems, symbols or words, used to authenticate writings or documents. --subdivision Seal under names of countries, cities, etc., and under names of individual persons and corporate bodies