Missing reference to System.Data.Linq

I have a newly created Website project in VS 2012. It indicates the Application Type is Class Library. I have the following code in my login module:

Imports GCF2014
Imports System.Data
Imports System.Data.Linq

Partial Class Account_Login
    Inherits System.Web.UI.Page

    Dim dc As gcfDataContext = New gcfDataContext

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
.

.
.
        End If

    End Sub

I get the following error when I try to run this module:

Compiler Error Message: BC30007: Reference required to assembly 'System.Data.Linq, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' containing the base class 'System.Data.Linq.DataContext'. Add one to your project.

Source Error:


 

Line 6:      Inherits System.Web.UI.Page
Line 7:  
Line 8:      Dim dc As gcfDataContext = New gcfDataContext
Line 9:  
Line 10:     Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
 

I have System.Data.Linq in my list of references. I am running as ASP.Net 4.0.

Why am I getting this error?