Riemann-Stieltjes operators on some general spaces on the unit ball and their essential norm

The objective of this paper is to find an estimation of the essential norm of Riemann-Stieltjes operator from the spaces $F(p,q,s)$ ( general function space) and $H(p,q,\phi )$ (mixed-norm space) into Zygmund-type space in the unit ball of ${\mathbb{C}}^n$.