1. Turán, P. On Some Open Problems of Approximation Theory.J. Approx. Theory, 1980, 29: 23–85.
2. Chak, A.M., Sharma, A. and Szabados, J. On a Problem of P. Turán.Studia Sci. Math. Hungar., 1980, 15: 441–455.
3. Bajpai, P. and Saxena, R.B. Some Regular and Singular Pairs of Birkhoff Interpolation.Demonstratio Math., 1989, 12: 583–597.
4. Surányi, J. and Turán, P. Notes on Interpolation, I.Acta Math. Acad. Sci., Hungar., 1955, 6: 67–80.
5. Lorentz, G.G., Jetter, K. and Riemenschneider, S.D. “Birkhoff Interpolation.” Addison Wesley Pub. Co., Reading, Massachusetts, London, 1983.