44 The duty to interpret a treaty as a whole has been clarified by the Permanent Court of International Justice in Competence of the I.L.O. to Regulate Agricultural Labour (1922), PCIJ, Series B, Nos. 2 and 3, p. 23. This approach has been followed by the International Court of Justice in Ambatielos Case (1953) ICJ Reports, p. 10; Reservations to the Convention on the Prevention and Punishment of the Crime of Genocide (1951) ICJ Reports, p. 15; and Case Concerning Rights of United States Nationals in Morocco (1952) ICJ Reports, pp. 196–199. See also I. Brownlie, Principles of Public International Law, 5th ed. (Clarendon Press, 1998), p. 634; G. Fitzmaurice, "The Law and Procedure of the International Court of Justice 1951–1954: Treaty Interpretation and Other Treaty Points", 33 British Yearbook of International Law (1957), p. 211 at p. 220; A. McNair, The Law of Treaties (Clarendon Press, 1961), pp. 381–382; I. Sinclair, The Vienna Convention on the Law of Treaties (Manchester University Press, 1984), pp. 127–129; M.O. Hudson, La Cour Permanente de Justice Internationale (Editions A Pedone, 1936), pp. 654–659; and L.A. Podesta Costa and J.M. Ruda, Derecho Internacional Público, Vol. 2 (Tipográfica, 1985), p. 105.