title: GDS- expedia - booking.com
body: <p>Can anyone show me the way or provide some good links to read in order to
  send hotel availability from a reservation system to GDS networks -  expedia booking.com</p>
  
  <p>Do i have to make something like a xml file?
  Any API available in php?</p>
  
  <p>thanks for any hint-help!!!</p>