Developing countries mathematicians should try to resolve economical paradox that forbid to integrate non-formal transactions in GIP. But taking in account GIP is a tool designed by USA for European countries, stating WWII was comparable to Great Depression, a tool used to measure a country's necessities, based on its ability to pay back, you'd better try to formulate an economical system better adapted to your specific economies and traditions.

By doing cooperation with developed country for clean development mechanism

There is so much wrong with third world economic models, they are not home grown and are operating for the benefit and with a focus on developed nations and economic rapists. Many are raped internally by her leaders and externally by a skewed economic system that disfavours weak nations. In my country we have this quip about our problematic destruction of our own economy: we buy what we don't produce and we produce what we dont buy. There are so many problems. Resource rich third world countries concentrate on exporting unprocessed natural resources thereby exporting jobs and part of their wealth. They also have subsidies in so many sectors and have uneconomic rates and structures feeding on the income from natural resource export.