Fuentes de información:
https://www.zoho.com/crm/zohocrm-pricing.html
http://blog.nextup.com.mx/como-usar-las-herramientas-del-crm-salesforce-para-incrementar-ventas
https://www.sumacrm.com/precios.php
http://www.christiamalvarado.com/marketing/las-5-mejores-herramientas-de-crm-para-pymes/
https://www.zoho.com/crm/zohocrm-pricing.html
http://info.sugarcrm.com/trial.html
https://www.salesforce.com/editions-pricing/sales-cloud/?d=70130000000i7ze&internal=true
