1. [1] D. Avitzour, Free products of $C\sp{\ast}$-algebras, Trans. Amer. Math. Soc. 271 (1982), no. 2, 423–435.
2. [2] B. Blackadar, $K$-theory for operator algebras, Mathematical Sciences Research Institute Publications, vol. 5, Springer-Verlag, New York, 1986.
3. [3] J. Cuntz, $K$-theoretic amenability for discrete groups, J. Reine Angew. Math. 344 (1983), 180–195.
4. [4] J. Cuntz, The $K$-groups for free products of $C\sp{\ast}$-algebras, Operator algebras and applications, Part I (Kingston, Ont., 1980), Proc. Sympos. Pure Math., vol. 38, Amer. Math. Soc., Providence, R.I., 1982, pp. 81–84.
5. [5] E. Germain, $KK$-theory of reduced free product $C^{\ast}$- algebras with amalgamation over $C(X)$, Ph.D. dissertation, University of California at Berkeley, 1994.