Is it best to use HTTP REFERER for redirects or use some other method?

history.go(-1);

<form action="login" method="post">
<input type="hidden" name="url" value="... whatever the current url is ...">
<input type="text" name="username">
<input type="text" name="password">
</form>

Protected Sub doRedirect(ByVal sender As Object, ByVal e As System.EventArgs)
    If Not Request.QueryString("rtn") Is Nothing Then
        Response.Redirect(Request.QueryString("rtn").ToString)
    ElseIf Me.hidden_return.Value <> "" Then
        Response.Redirect(Me.hidden_return.Value)
    ElseIf Not Request.UrlReferrer Is Nothing AndAlso Request.UrlReferrer.Segments(Request.UrlReferrer.Segments.Length - 1) <> "login.aspx" Then
        Response.Redirect(Request.UrlReferrer.ToString)
    Else
        Response.Redirect("default.aspx")
    End If
End Sub