diff --git a/lib/paypal/recurring.rb b/lib/paypal/recurring.rb
index 430da07..6c3fc91 100644
--- a/lib/paypal/recurring.rb
+++ b/lib/paypal/recurring.rb
@@ -11,6 +11,7 @@ module Recurring
     autoload :Request, "paypal/recurring/request"
     autoload :Response, "paypal/recurring/response"
     autoload :Version, "paypal/recurring/version"
+    autoload :Utils, "paypal/recurring/utils"
 
     ENDPOINTS = {
        :sandbox => {
diff --git a/lib/paypal/recurring/notification.rb b/lib/paypal/recurring/notification.rb
index 97735c9..9f3014e 100644
--- a/lib/paypal/recurring/notification.rb
+++ b/lib/paypal/recurring/notification.rb
@@ -1,8 +1,24 @@
 module PayPal
   module Recurring
     class Notification
+      extend PayPal::Recurring::Utils
+
       attr_reader :params
 
+      mapping({
+        :type           => :txn_type,
+        :transaction_id => :txn_id,
+        :fee            => [:mc_fee, :payment_fee],
+        :reference      => [:rp_invoice_id, :custom, :invoice],
+        :payment_id     => :recurring_payment_id,
+        :amount         => [:amount, :mc_gross, :payment_gross],
+        :currency       => :mc_currency,
+        :status         => :payment_status,
+        :payment_date   => [:time_created, :payment_date],
+        :seller_id      => :receiver_id,
+        :email          => :receiver_email
+      })
+
       def initialize(params = {})
         self.params = params
       end
@@ -13,10 +29,6 @@ def params=(params)
         end
       end
 
-      def type
-        params[:txn_type]
-      end
-
       def express_checkout?
         type == "express_checkout"
       end
@@ -36,47 +48,19 @@ def response
       end
 
       def valid?
-        completed? && verified? && params[:receiver_email] == PayPal::Recurring.email && params[:receiver_id] == PayPal::Recurring.seller_id
+        completed? && verified? && email == PayPal::Recurring.email && seller_id == PayPal::Recurring.seller_id
       end
 
       def completed?
         status == "Completed"
       end
 
-      def transaction_id
-        params[:txn_id]
-      end
-
-      def fee
-        params[:mc_currency]
-      end
-
-      def reference
-        params[:rp_invoice_id]
-      end
-
-      def payment_id
-        params[:recurring_payment_id]
-      end
-
       def next_payment_date
         Time.parse(params[:next_payment_date]) if params[:next_payment_date]
       end
 
       def paid_at
-        Time.parse params[:time_created] if params[:time_created]
-      end
-
-      def amount
-        params[:amount]
-      end
-
-      def currency
-        params[:mc_currency]
-      end
-
-      def status
-        params[:payment_status]
+        Time.parse(payment_date) if payment_date
       end
 
       def verified?
diff --git a/lib/paypal/recurring/response/base.rb b/lib/paypal/recurring/response/base.rb
index 14a98a2..007c401 100644
--- a/lib/paypal/recurring/response/base.rb
+++ b/lib/paypal/recurring/response/base.rb
@@ -2,24 +2,9 @@ module PayPal
   module Recurring
     module Response
       class Base
-        attr_accessor :response
+        extend PayPal::Recurring::Utils
 
-        def self.mapping(options = {})
-          options.each do |to, from|
-            class_eval <<-RUBY
-              def #{to}
-                @#{to} ||= begin
-                  from = [#{from.inspect}].flatten
-                  name = from.find {|name| params[name]}
-                  value = nil
-                  value = params[name] if name
-                  value = send("build_#{to}", value) if respond_to?("build_#{to}", true)
-                  value
-                end
-              end
-            RUBY
-          end
-        end
+        attr_accessor :response
 
         mapping(
           :token           => :TOKEN,
diff --git a/lib/paypal/recurring/utils.rb b/lib/paypal/recurring/utils.rb
new file mode 100644
index 0000000..d11e5ce
--- /dev/null
+++ b/lib/paypal/recurring/utils.rb
@@ -0,0 +1,22 @@
+module PayPal
+  module Recurring
+    module Utils
+      def mapping(options = {})
+        options.each do |to, from|
+          class_eval <<-RUBY
+            def #{to}
+              @#{to} ||= begin
+                from = [#{from.inspect}].flatten
+                name = from.find {|name| params[name]}
+                value = nil
+                value = params[name] if name
+                value = send("build_#{to}", value) if respond_to?("build_#{to}", true)
+                value
+              end
+            end
+          RUBY
+        end
+      end
+    end
+  end
+end
diff --git a/spec/paypal/notification_spec.rb b/spec/paypal/notification_spec.rb
index f5c930a..1302f5e 100644
--- a/spec/paypal/notification_spec.rb
+++ b/spec/paypal/notification_spec.rb
@@ -11,6 +11,23 @@
     subject.should be_recurring_payment
   end
 
+  describe "#reference" do
+    it "returns from recurring IPN" do
+      subject.params[:rp_invoice_id] = "abc"
+      subject.reference.should == "abc"
+    end
+
+    it "returns from custom field" do
+      subject.params[:custom] = "abc"
+      subject.reference.should == "abc"
+    end
+
+    it "returns from invoice field" do
+      subject.params[:invoice] = "abc"
+      subject.reference.should == "abc"
+    end
+  end
+
   context "when successful" do
     use_vcr_cassette "notification/success"