--- a/discovery-api/Overview.src.html	Mon Feb 04 13:47:41 2013 +0100
+++ b/discovery-api/Overview.src.html	Mon Feb 04 14:00:59 2013 +0100
@@ -993,7 +993,7 @@
       <p>
         The <dfn>list of available service records</dfn> is a single dynamic internal lookup table within user agents
         that is used to track all the services that have been discovered and are available in the current network at
-        any given time. At any point during the running of either of the two <a>service discovery mechanisms</a> then
+        the current time. At any point during the running of either of the two <a>service discovery mechanisms</a> then
         existing entries within this table can be updated, entries can be added and entries can be removed as the
         status of networked services changes according to the rules defined in this specification.
       </p>
@@ -1204,10 +1204,11 @@
         <p>
           The user agent MUST issue all <a title="search request for UPnP root devices">search requests for UPnP root
           devices</a> with a HTTP request line equal to <code>M-SEARCH * HTTP/1.1</code>, with a HOST header equal to
-          the reserved multicast address and port of <code>239.255.255.250:1900</code>, a MAN header equal to
-          <code>ssdp:discover</code>, an ST header equal to <code>upnp:rootdevice</code> and a user-agent defined MX
-          header equal to a <dfn>maximum UPnP advertisement response wait time</dfn> value between <code>1</code> and
-          <code>5</code> seconds.
+          the reserved multicast address and port of <code>239.255.255.250:1900</code> and a MAN header equal to
+          <code>ssdp:discover</code>. The <a>user agent</a> must also send an ST header with this HTTP request equal to
+          the String value of <code>ssdp:all</code> or <code>upnp:rootdevice</code> or a single <a>valid service
+          type</a> token. The user-agent MUST also send an MX header equal to a <dfn>maximum UPnP advertisement
+          response wait time</dfn> value between <code>1</code> and <code>5</code> seconds with this HTTP request.
         </p>
         <p>
           The user agent MUST listen for any incoming responses to any <a>search request for UPnP root devices</a>.