1. M. B. Abrahamse, and R. G. Douglas, A class of subnormal operators related to multiply connected domains, Advances in Math., 19 (1976), 106–148.
2. M. B. Abrahamse and R. G. Douglas, Operators on multiply connected domains, Proc. of the Royal Irish Acad., 74A (1974), 135–141.
3. V. M. Adamjan and D. Z. Arov, On unitary couplings of semiunitary operators, Dokl. Akad. Nauk Arm. SSR, XLIII (1966) [in Russian]; English transl., Amer. Math. Soc. Transi., 95 (1970), 75–129.
4. J. Agler, Rational dilation on an annulus, Annals of Mathematics, 121 (1985), 537–563.
5. D. Alpay and V. Vinnikov, Indefinite Hardy spaces on finite bordered Riemann surfaces, J. Functional Analysis, 172 (2000), 221–248.