Integrated surveys for river basin development proccedings of the fourth international seminar, 20-25 Oct., 1969 - ITC-UNESCO Seminar on Integrated Surveys for iver Basin Development, 4th, Delft, 1969; Broek, J. M> van den. (Delft ITC-UNESCO Centre for Integrated Surveys, [1969]., 1969)
Keywords: Water resources development -- Congresses