 Selected Readings. Salmon (1971a) provides a detailed statement and defense of the SR model. This essay, as well as papers by Jeffrey (1969) and Greeno (1970) which defend views broadly similar to the SR model, are collected in Salmon (1971b). Additional discussion of the model as well as a more recent characterization of “objective homogeneity” can be found in Salmon (1984). Cartwright (1979) contains some influential criticisms of the SR model. Theorems specifying the precise extent of the underdetermination of causal claims by evidence about statistical relevance relationships can be found in Spirtes, Glymour and Scheines (1993 [2000: chapter 4]). For additional discussion of “screening off” and the principle of the common cause, see the entry on  Reichenbach’s Principle of the Common Cause.