1. World Health Statistics Annual 1967, Vol. I (WHO, Geneva 1970).
2. World Health Statistics Annual 1968, Vol. I (WHO, Geneva 1971).
3. World Health Statistics A nnual 1969, Vol. I (WHO, Geneva 1972).
4. World Health Statistics Annual 1970, Vol. I (WHO, Geneva 1973).
5. World Health Statistics A nnual 1971, Vol. I (WHO, Geneva 1974).