A method and apparatus for searching a program guide comprising program information for a plurality of different program sources. The program information includes the titles of the programs, the channel on which each program is to be shown, and the time at which each program is to be shown. The viewer...http://www.google.com.hk/patents/US5635989?utm_source=gb-gplus-share專利 US5635989 - Method and apparatus for sorting and searching a television program guide
