diff --git a/README.md b/README.md
index e69de29..09f05aa 100644
--- a/README.md
+++ b/README.md
@@ -0,0 +1,8 @@
+######################
+Analytic Operations Module
+######################
+
+
+The *Analytic Operations Module* adds the concept of analytic account general
+in invoice, purchase, sale. This allows added the account analytic to the lines of
+operation more fast.
diff --git a/__init__.py b/__init__.py
index 542096c..8a49cb1 100644
--- a/__init__.py
+++ b/__init__.py
@@ -2,7 +2,7 @@
 # this repository contains the full copyright notices and license terms.
 
 from trytond.pool import Pool
-from . import purchase, sale
+from . import invoice, purchase, sale
 
 __all__ = ['register']
 
@@ -13,8 +13,10 @@ def register():
         purchase.PurchaseLine,
         sale.Sale,
         sale.SaleLine,
-        module='analytic_operation', type_='model')
+        invoice.Invoice,
+        invoice.InvoiceLine,
+        module='analytic_operations', type_='model')
     Pool.register(
-        module='analytic_operation', type_='wizard')
+        module='analytic_operations', type_='wizard')
     Pool.register(
-        module='analytic_operation', type_='report')
+        module='analytic_operations', type_='report')
diff --git a/invoice.py b/invoice.py
new file mode 100644
index 0000000..6539ba9
--- /dev/null
+++ b/invoice.py
@@ -0,0 +1,39 @@
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
+from trytond.pool import Pool, PoolMeta
+from trytond.model import ModelView, ModelSQL, fields
+from trytond.pyson import Eval
+
+from trytond.exceptions import UserError
+
+class Invoice(metaclass=PoolMeta):
+    'Account Invoice'
+    __name__ = 'account.invoice'
+
+    _states = {
+        'readonly': Eval('state') != 'draft',
+        }
+
+
+    account_analytic = fields.Many2One('analytic_account.account', 'Analytic Account', required=True,
+                                       domain=[('type', '=', 'normal')],
+                                       states=_states)
+
+    
+class InvoiceLine(metaclass=PoolMeta):
+      'Invoice Line'
+      __name__ = 'account.invoice.line'
+
+      @fields.depends('product', 'unit', '_parent_invoice.type', 'analytic_accounts',
+                      '_parent_invoice.party', 'party', 'invoice', 'invoice_type',
+                      '_parent_invoice.account_analytic', '_parent_invoice.invoice_date',
+                      '_parent_invoice.accounting_date','company', methods=['_get_tax_rule_pattern'])
+      def on_change_product(self):
+          super(InvoiceLine, self).on_change_product()
+          self.analytic_accounts = tuple()
+          try:
+              self.analytic_accounts += ({'root': self.invoice.account_analytic.root,
+                                          'account': self.invoice.account_analytic},) 
+          except:
+              pass
+
diff --git a/invoice.xml b/invoice.xml
new file mode 100644
index 0000000..abf0d8b
--- /dev/null
+++ b/invoice.xml
@@ -0,0 +1,11 @@
+<?xml version="1.0"?>
+<!--This file file is part of Tryton. The COPYRIGHT file at the top level of this repository contains the full copyright notices and license terms. -->
+<tryton>
+    <data>
+	<record model="ir.ui.view" id="invoice_view_form">
+	    <field name="model">account.invoice</field>
+	    <field name="inherit" ref="account_invoice.invoice_view_form"/>
+	    <field name="name">invoice_form</field>		
+    	</record>
+    </data>
+</tryton>
diff --git a/locale/es.po b/locale/es.po
index 2ceeb14..0771462 100644
--- a/locale/es.po
+++ b/locale/es.po
@@ -2,6 +2,10 @@
 msgid ""
 msgstr "Content-Type: text/plain; charset=utf-8\n"
 
+msgctxt "field:account.invoice,account_analytic:"
+msgid "Analytic Account"
+msgstr "Cuenta Analítica"
+
 msgctxt "field:purchase.purchase,account_analytic:"
 msgid "Analytic Account"
 msgstr "Cuenta Analítica"
diff --git a/purchase.py b/purchase.py
index 31ae531..5454878 100644
--- a/purchase.py
+++ b/purchase.py
@@ -10,11 +10,13 @@ class Purchase(metaclass=PoolMeta):
     'Purchase Analytic Operation'
     __name__ = 'purchase.purchase'
 
-    account_analytic = fields.Many2One('analytic_account.account',
-                                       'Analytic Account', required=True,
-                                       domain=[
-                                           ('type', '=', 'normal'),
-                                       ])
+    _states = {
+        'readonly': Eval('state') != 'draft',
+        }
+
+    account_analytic = fields.Many2One('analytic_account.account', 'Analytic Account', required=True,
+                                       domain=[('type', '=', 'normal')],
+                                       states=_states)
 class PurchaseLine(metaclass=PoolMeta):
     'Purchase Line Analytic Operation'
     __name__ =  'purchase.line'
diff --git a/tryton.cfg b/tryton.cfg
index aef0cdc..c18fc81 100644
--- a/tryton.cfg
+++ b/tryton.cfg
@@ -8,3 +8,4 @@ depends:
 xml:
     purchase.xml
     sale.xml
+    invoice.xml
diff --git a/view/invoice_form.xml b/view/invoice_form.xml
new file mode 100644
index 0000000..4ef0621
--- /dev/null
+++ b/view/invoice_form.xml
@@ -0,0 +1,10 @@
+<?xml version="1.0"?>
+<!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
+this repository contains the full copyright notices and license terms. -->
+<data>
+ <xpath
+     expr="/form/field[@name='reference']" position="after">
+       <label name="account_analytic"/>
+       <field name="account_analytic" xexpand="1"/>
+  </xpath>
+</data>