By taking this table, we realize what the main point of this research is and where we have came to a halt. As I said before, we are facing two problems side by side at the same time. On the one hand we have the existence of communal goods whose property rights are difficult to be defined, and on the other hand, we have a great number of legislators with different points of view. Because of this fact, local externalities cannot take into account the global problem which is the combination of national ones.