Invites ,the regional economic commissions and the Economic Projections and Programming Centre to intensify their co-operation with and assistance to the regional planning ins~itutes, a_nd to help i~ the l?rom~- tion of exchange of information on experience in this field among regional economic commissions _and. other United Nations bodies concerned and the d1ffus10n of this information by all appropriate means, including the organization of symposia and seminars ;