1. Adamjan, V.M., Arov, D.Z.: On unitary coupling of semiunitary operators. Am. Math. Soc. Transl. (2), 13:75–129 (1970). English translation of the Russian original, Mat. Issled. 1 (1966) vyp. 2, 3–64
2. Amann, H.: Linear and Quasilinear Parabolic Problems, vol. I. Birkhäuser, Basel (1995)
3. Andô, T.: On a pair of commutative contractions. Acta Sci. Math. (Szeged) 24, 88–90 (1963)
4. Andô, T.: Unitary dilation for a triple of commuting contractions. Bull. Acad. Polon. Sci. Sér. Sci. Math. Astronom. Phys. 24(10), 851–853 (1976)
5. Archer J.R.: Positivity and the existence of unitary dilations of commuting contractions. In: The Extended Field of Operator Theory, Operator Theory Advances and Applications, vol. 171. Birkhäuser, Basel, pp. 17–35 (2007)