eiru_contract_reference/model.py

# -*- coding: utf-8 -*-
from openerp import models, fields, api

class StockLocation(models.Model):
    _inherit = 'stock.location'

    account_analytic_account_id = fields.Many2one('account.analytic.account', 'Contrato', domain="[('state','in',['open','pending'])]")

class AccountInvoice(models.Model):
    _inherit = 'account.invoice'

    account_analytic_account_id = fields.Many2one('account.analytic.account', 'Contrato', domain="[('state','in',['open','pending'])]")