Sen, (Calcutta)International Symposium on Plant Cell Culture in Crop Improvement International Symposium on Plant Cell Culture in Crop Improvement (Manila)International Symposium on Remote Sensing of Environment (San Jose)International Symposium on Remote Sensing of Environment (Wash.)International Symposium on the Chemistry of Cement (Halifax)International Symposium on Tailings and Effluent Management (Ann Arbor)International Symposium on Remote Sensing of Environment The Fifth International Symposium on the Chemistry of Cement Lectures international symposium on macromolecular chemistry (Waterbury)International Symposium on Ozone for Water and Wastewater Treatment