1. J. Aczèl: Lectures on Functional Equations and their Applications’, Academic Press, New York—London, 1966. (pp. 234–244 )
2. J. Aczèl: The notion of mean values’, Norske Vid. Selsk. Forh. Trondheim
19 (1946), 83–86.
3. G. Almkvist and B. Berndt: Gauss, Landen, Ramanujan, the arithmetic-geometric mean, ellipses, 7r and the Ladies Diary’, Amer. Math. Monthly
95 (1988), 585–607.
4. J. Arazy, T. Cleasson, S. Janson and J. Peetre: Means and their iterations’, pages 191–217 In: Proceedings of the Nineteenth Nordic Congress of Mathematicians, Reykjavik, 1984.
5. E.F. Beckenbach: A class of mean value functions’, Amer. Math. Monthly
57 (1950), 1–6.