The non-oil developing countries and OPEC: Coalition or conflict?

For a time in the mid-1970s, “Third World solidarity” was at its zenith and the prospect of a new international economic order appeared to be within reach. But by the Cancun Summit in 1981 the schism between the oil exporting developing countries and the non-oil exporting developing countries had become apparent. What are the determinants of relationships between these two groups of countries? What are the prospects for the second half of the 1980s?