An apparatus is disclosed which enables efficient search of a particular file out of a multiplicity of files arranged on shelves, such that a display light, such as light-emitting diode, lights to externally indicate the location of the file only when a signal receiver attached to the file receives a...http://www.google.de/patents/US5063380?utm_source=gb-gplus-sharePatent US5063380 - Discrete object searching apparatus for search of discrete files and the like
