OpenTK audio file loading

Hi!

I am trying to make a sound loading class for my game, But when I try to use the code provided in the openTK manual, it can't find the AudioReader class.

These are the references:

using OpenTK;
using OpenTK.Audio;
using OpenTK.Audio.OpenAL;

And this is were the magic would have happen if it worked...

          AudioContext AC = new AudioContext();
          uint MyBuffer;
          AL.GenBuffers( 1, out MyBuffer );
 
          AudioReader sound = new AudioReader("test.wav");
          AL.BufferData(MyBuffer, sound.ReadToEnd());

Everything seems fine except for the AudioReader which Visual studio can't recognise.

Have I missed something important? To me it seems so, please enlighten me about this issue!