On utilising the spectral representation of selfadjoint operators in Hilbert spaces, some trapezoidal inequalities for various classes of continuous functions of such operators are given.
S. S. Dragomir. "Some Trapezoidal Vector Inequalities for Continuous Functions of Selfadjoint Operators in Hilbert Spaces." Abstr. Appl. Anal. 2011 1 - 13, 2011. https://doi.org/10.1155/2011/941286