The common standards for the purchase or tender for work in the civilian sector is said to be giving a link to obtain offers companies the types of request different prices officer an announcement in newspapers or soliciting, negotiation or direct purchase standard called concessions In this case, the contractor is the only applicant or supplement tender the same contractor or to be the only local product in the event that the laws in the state give priority to products . all the powers of the purchase followed (upper ceilings for purchase) . committees ... etc.