Sharma, Ajay K. “Norm of a Composition Operator from the Space of Cauchy Transforms into Zygmund-Type Spaces”.
Ukrains’kyi Matematychnyi Zhurnal
, vol. 71, no. 12, Dec. 2019, pp. 1699-11,
https://umj.imath.kiev.ua/index.php/umj/article/view/367
.