1. Bateman, H., Erdélyi, A.: Higher Transcendental Functions [Russian translation], vol. 2, Nauka, Moscow, (1974).
2. Fryant, A.J. 1977. Growth and complete sequences of generalized axisymmetric potentials. J. Approx. Theorey 19: 361–370.
3. Fryant, A.J., and H. Shankar. 1987. Fourier coefficients and growth of harmonic functions. Internat. J. Math. Math. Sci. 10 (3): 443–452.
4. Gilbert, R.P.: Function Theoretic Methods in Partial Differential Equations, Math. in Science and Engineering, Vol. 54, Academic Press, New York, (1969).
5. Juneja, O.P., G.P. Kapoor, and S.K. Bajpai. 1976. On the $$(p, q)$$-order and lower $$(p, q)$$-order of an entire function. Journal fur die Reine und Angewandte Mathematik 282: 53–67.