http://greenmousestudio.com/en/prestashop-enhancements > Mix codes and suggestions to enhance
https://www.prestashop.com/forums/topic/274240-add-message-to-order_confhtml/ > Increase messagens in mail send to clients
https://webkul.com/blog/how-to-modify-fields-list-in-prestashop/ >> add extra fields with override controller.