title: Requirements for a WS to be considered restful
body: <p>in an answer from <a href="https://stackoverflow.com/questions/1261954/what-gets-classified-as-a-restful-web-service">What gets classified as a RESTful Web Service</a> it is stated:</p>
  
  <blockquote>
    <p>There are a number of other constraints that a service must respect in order to be considered RESTful</p>
  </blockquote>
  
  <p>Where could I find the list of constraints?</p>
  
  <p>Thanks.</p>