They will be understood, consequently, happened or perfected the taxable facts and been born the tributary obligation: 1. In the sale of corporal personal property: b) In all the other cases different from the mentioned ones in literal previous (Sales to beings public) 4, when the invoice is emitted or equivalent document that puts record of the operation or is pleased the price or since the real delivery becomes of the goods, according to is what it happens first. Omissis 3. In the benefit of services: omissis e) In all the other cases different from mentioned in literal previous (Services Public and Telecommunications, other services of tract successive, served to Beings Public and Originating services of the outside) 5, when the equivalent invoices or documents are emitted by that the service gives, executes the benefit, is pleased, that is indispensable the return, or gives or puts at the disposal of the purchaser the good that had been object of the service, according to is what it happens first. Seen the previous thing, we can conclude then that our legislator raises four possible situations that make be born the tributary obligation as far as the sale from corporal personal property and or benefit of services to nongovernmental beings, first of them, is the emission of the invoice, that obviously would have to be the generating fact of the obligation par excellence as much and inasmuch as it constitutes a contentivo document of all the information necessary to determine the tribute. Secondly the norm makes mention to the emission of a document equivalent to the invoice nevertheless does not define as they are these documents, we could say that a document equivalent to the invoice could be a Note of Delivery which is discarded by virtue of which this document necessarily implies the delivery of the goods which constitutes in itself a generating fact of the obligation; we could also speak of the Order of purchase, which reunites the necessary elements for the determination of the tribute, except for being a contract obligee for the parts, despite the emission of this one depends on the buyer and not on the salesman, being who the generating fact of the tribute is the sale and it purchase is not then discarded; another document used by some companies, is Pre-invoices, which doubtless reunite all the requirements necessary to make be born the obligation and determine the tribute, despite it is not a document of spread use and much less of use obligatory.