11. CUSTOM CAN BE COMPARED the custom are the acts repeated by a group of people, thus is clear that it defers in each pas and each part or cities of the same, thus the comparatistas must consider east element of the right, nevertheless, we have not had at sight comparatistas studies on this source of the right. Custom can be compared, thus is clear that Peruvian custom with German, Peruvian can be compared with Bolivian, Peruvian with French, Peruvian with Italian, Peruvian with Spanish, Peruvian with Argentinean, Peruvian with Chilean, Peruvian with Uruguayan, Peruvian with Paraguayan, Uruguayan with Paraguayan, Argentinean with Chilean, Argentinean with Paraguayan, Italian, Italian Argentinean with French, French with German, German with Italian, among others assumptions, and in addition is clear that can exist cases in which are spoken customary compared civilian, procedural compared civilian, penal compared, procedural compared penitentiary, constitutional compared, procedural compared, registry compared constitutionalist, labor compared, procedural labor compared, tributary compared, notarial compared, customs compared, sanitary compared, medical compared, among others supposed. 12. DOCTRINE CAN BE COMPARED the doctrine are the published commentaries of the jurisconsultos, as they can be treaty writers, authors and contributors, having each of these hierarchy within the doctrinary ones, nevertheless, in the Peruvian right this fact is not taken into account and in England it even distinguishes authority books of whom they are not it, thus exist books that are not authority books, sure est that in the Peruvian state east subject has not developed. Doctrine can be compared, in such sense is possible that Peruvian doctrine with Mexican is compared, Mexican with American, Peruvian with American, Peruvian with French, Peruvian with German, Peruvian with Italian, Peruvian with Spanish, Peruvian with Bolivian, Peruvian with Argentinean, Peruvian with Paraguayan, Peruvian with Uruguayan, Peruvian with Chilean, Ecuadorian, Ecuadorian Chilean with French, French with Chilean, Chilean with Bolivian, among others supposed.