[1] FABRITIIS C D, GENTILI G, SARFATTI G. Quaternionic Hardy spaces[J]. arXiv:1404.1234v2, 2015.
[2] SARFATTI G. Elements of function theory in the unit ball of quaternions[D]. Firenze: Università di Firenze, 2013.
[3] CHEN Y W, REN G B. De la Vallée Poussin means in Hardy spaces[J]. Results in Mathematics, 2017, 72(3): 1585-1600. DOI: 10.1007/s00025-017-0712-6.
[4] STOROZÉNKO E A. Approximation of functions of class H
p,0<p≤1[J]. Math USSR-Sb, 1978, 34: 527-545. DOI: 10.1070/SM1978v034n04ABEH001228.
[5] 王志军, 陈英伟. 有界对称域上Ω代数中的Jackson 定理[J]. 河北大学学报(自然科学版), 2014, 34(4): 342-346. DOI: 10.3969/j.issn.1000 -1565.2014.04.002.
[6] WANG M Z, REN G B. Jacksons theorem on bounded symmetric domains[J]. Acta Mathematica Sinica(English Series), 2007, 23(8): 1391-1404. DOI: 10.1007/s10114-007-0953-5.
[7] GAL S G, SABADINI I. Approximation by polynomials on quaternionic compact sets[J]. Mathematical Methods in the Applied Sciences, 2015, 38(14): 3063-3074. DOI: 10.1002/mma.3281.
[8] GAL S G. Quantitative approximations by convolution polynomials in Bergman spaces[J]. Complex Analysis and Operator Theory, 2018, 12(2): 355-364. DOI: 10.1007/s11785-016-0601-0.
[9] GENTILI G, STOPPATPO C, STRUPPA D C. Regular functions of a quaternionic variable[M]. Heidelberg: Springer, 2013.
[10] DEVORE R A, LORENTZ G G. Construction approximation[M]. Berlin: Springer-Verlag, 1993.
[11] GARNETT J B. Bounded analytic functions[M]. New York: Academic Press, 1981.
