怎么解决web service circular reference 问题

下面是一个非常简单的例子:
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

namespace WebService1
{

[Serializable]
public class Person
{
private Person friend;
private String name;

public String Name
{
get { return name; }
set { name = value; }
}

public Person Friend
{
get { return friend; }
set { friend = value; }
}
}
}

using System;
using System.Data;
using System.Web;
using System.Collections;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.ComponentModel;

namespace WebService1
{
/// <summary>
/// Summary description for Service1
/// </summary>
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[ToolboxItem(false)]
public class Service1 : System.Web.Services.WebService
{

[WebMethod]
public Person HelloWorld()
{
Person him = new Person();
Person her = new Person();

him.Friend = her;
her.Friend = him;
return him;
}
}
}

运行 ASMX web service 将会得到下面的错误:

System.InvalidOperationException: There was an error generating the XML
document. --->
System.InvalidOperationException: A circular reference was detected while
serializing an object of type Person.

IBM 网站有一篇文章描述了这个问题:
http://www-106.ibm.com/developerwor...s-tip-j2eenet1/

各位兄弟，谁解决过这个问题