  We examine the electronic width ratios of Upsilon resonances below the BBbar
threshold by means of an effective (Cornell-type) QCD potential incorporating
1/m_b corrections obtained from a prior fit to the bottomonium spectrum. From
our analysis we conclude that the Upsilon(2S) and Upsilon(3S) states should
belong to the strong-coupling (nonperturbative) regime while the Upsilon(1S)
state should belong to the weak-coupling (perturbative) regime, in agreement
with a previous study based on radiative decays.
