What computer programs do travel agents use?

Agents usually use one or more general distribution systems (GDS) that show a multitude of information about most airlines. These GDS allow agents to research and sell travel along with issuing tickets. Some examples are Sabre, Apollo and Worldspan. In addition, good agents use the internet to search places like kayak.com or other travel internet sites for comparison to the GDS. Agents also use spreadsheets, Word, Excell and back-office accounting systems like Trams.