Smith, A. R., & Smith, A. R. 1. (1970). Models of manpower systems: The proceedings of a conference held at Oporto in september 1969, under the aegis of the NATO Scientific Affairs Division. London: English Universities Press.

Smith, Anthony Robert, and A. R. 1926- Smith. Models of Manpower Systems: The Proceedings of a Conference Held At Oporto in September 1969, Under the Aegis of the NATO Scientific Affairs Division. London: English Universities Press, 1970.

Smith, Anthony Robert, and A. R. 1926- Smith. Models of Manpower Systems: The Proceedings of a Conference Held At Oporto in September 1969, Under the Aegis of the NATO Scientific Affairs Division. London: English Universities Press, 1970.