Razor - unable to add System.Core to Web.Config - razor

Question

I am using ServiceStack (self hosted) with Razor.
I have an issue trying to add System.Core to the namespaces in the web.config file.
Specifically, I get a compilation error if I include System.Core in the web.config.
Compilation Error
Description: An error occurred during the compilation of a resource required to service this request. Please review the following specific error details and modify your source code appropriately.
Compiler Error Message: CS0234: The type or namespace name 'Core' does not exist in the namespace 'System' (are you missing an assembly reference?)
Source Error:
Line 12: using System;
Line 13: using System.Collections.Generic;
Line 14: using System.Core;
Line 15: using System.Data;
Line 16: using System.IO;
Extract of Web.config file:
<system.web.webPages.razor>
<host factoryType="System.Web.Mvc.MvcWebRazorHostFactory, System.Web.Mvc" />
<pages pageBaseType="ServiceStack.Razor.ViewPage">
<namespaces>
<add namespace="System" />
<add namespace="System.Core" /> **-> THIS GIVES AN ERROR**
<add namespace="System.Data" />
<add namespace="System.Linq" />
<add namespace="ServiceStack" />
<add namespace="ServiceStack.Html" />
<add namespace="ServiceStack.Razor" />
<add namespace="ServiceStack.Text" />
<add namespace="ServiceStack.OrmLite" />
<add namespace="Classifieds" />
<add namespace="Classifieds.ServiceModel" />
<add namespace="Classifieds.ServiceInterface" />
</namespaces>
</pages>

Answer 1

System.Core is not a namespace its is an assembly