Carrying out the patent documentations in the foreign countries massive classi ed under the different systems is very dif cult. It appeared a real need to carry out a uniform documentation in the world patent collection. This is why in accordance with the regulations of the multilateral international treaty “European Convention on the International Patent Classi cation” concluded in 1954 under the aegis of the Europe Counsel (EC) and World Intellectual Property Organization (WIPO), it was accepted to create a unique patent classi cation as a main or an additional means for the inventions uniform international classi cation and patent documentation.