- International Atomic Energy Agency (5)
- Food and Agriculture Organization of the United Nations (4)
- Symposium on the Reliability of Nuclear Power Plants (1)
- Symposium on the Use of Isotope and Radiation Techniques in Soil Physics and Irrigation Studies (1)
- Symposium on the Use of Isotopes and Radiation in Entomology (1)
- Symposium on the Use of Isotopes in Plant Nutrition and Physiology (1966 : Vienna, Austria) (1)
- Symposium on the Use of Radioisotopes in Soil-Plant Nutrition Studies (1)
- United Nations. Economic Commission for Europe (1)