Dudley's chaining integral is commonly used to bound Rademacher complexities. I recall seeing several papers give this as the reference
@ARTICLE{MR512411,
author = {Dudley, R. M.},
title = {Central limit theorems for empirical measures},
journal = {Ann. Probab.},
year = {1978},
volume = {6},
pages = {899--929 (1979)},
number = {6},
coden = {APBYAE},
fjournal = {The Annals of Probability},
issn = {0091-1798},
mrclass = {60F05 (28C20 60B10 60F17)},
mrnumber = {MR512411 (81k:60029a)},
mrreviewer = {P. R{\'e}v{\'e}sz}
}
but I don't think the result in question actually appears in that paper. Could anyone point me to the definitive reference?