Using GHIElectronics.NETMF.FEZ; is missing

I tried to blink a LED according to the tutorial. but the GHIElectronics.NETMF.FEZ; assembly is not there. I want to use the following codes. I have already installed the SDK4.2 and FEZ Cerbuino Bee board is used. Can any one give me a suggestion. please

using System;
using Microsoft.SPOT;
using System.Threading;
using Microsoft.SPOT.Hardware;
using GHIElectronics.NETMF.FEZ;
namespace MFConsoleApplication1
public class Program
public static void Main()
OutputPort LED;
LED = new OutputPort((Cpu.Pin)FEZ_Pin.Digital.LED, true);
while (true)

Thanks mate.I’ll check it. I have a project on Encryption for e-Health supervisor advised me to use RC5