For some authors pool is just as the poster, and for others he is something different, and they even speak of pool aeronautical, in such sense it is clear that it deserves the corresponding studies. Pool is worked by the doctrine little and in the mercantile and enterprise legislation and it does not find norms general, but it only exists some norms on pool aeronautical in the positive right. Thus it is clear that consulting several books of enterprise right it has not been possible to find definitions that can guide to us in the present investigation, nevertheless, others consider that is different from the poster or kartel, of such form that can be different. In such sense we will define to pool like an assumption of enterprise concentration very similar to the poster, but narrow bows but, in such sense Earl R. KOHLER it needs on pool the following thing: it is a close combination of companies but that the cartels.

In her, each company conserves its technical manual, but the bows unite that them are but strong. Not only one regulates the production and the prices, but the bottoms are given to a common box, distributing itself later proportionally, in agreement with a determined plan previously. The separation between this type of combination and the cartels are not very precise, then, generally, indicates an agreement between independent producers that delegate in a central organism the inspection of the sale of products. They are based on contracts written, in which is stipulated and penal clauses for the violations of the same are included. Several classes of pool are distinguien, that agree with the diverse types of cartels. But the important ones are the following: pool of production, pool territorial or of market, the one of sales, the one of prices and the one of patents. One of the examples of pool in which one verifies the peculiar characteristic of the distribution of income and gains; it was of the North American railway companies until 1870, as, by means of this procedure, they avoided the incentive of the diminution of the tariffs.