  We re-examine the interesting possibility of utilizing the Glashow resonance
(GR) channel nu_ebar + e^- to W^- to anything to discriminate between the UHE
cosmic neutrinos originating from p-gamma and pp collisions in an optically
thin source of cosmic rays. We propose a general parametrization of the initial
neutrino flavor composition by allowing the ratios Phi^{p gamma}_{pi^-}/Phi^{p
gamma}_{pi^+} and Phi^{pp}_{pi^-}/Phi^{pp}_{pi^+} to slightly deviate from
their conventional values. A relationship between the typical source parameter
kappa = (Phi^{p gamma}_{pi^+} + Phi^{p gamma}_{pi^-})/(Phi^{pp}_{pi^+} +
Phi^{pp}_{pi^-} + Phi^{p gamma}_{pi^+} + Phi^{p gamma}_{pi^-}) and the working
observable of the GR R_0 = Phi^T_{nu_ebar}/ (Phi^T_{nu_mu} + Phi^T_{nu_mu}) at
a neutrino telescope is derived, and the numerical dependence of R_0 on kappa
is illustrated by taking account of the latest experimental data on three
neutrino mixing angles. It is shown that a measurement of R_0 is in principle
possible to identify the pure p-gamma interaction (kappa =1), the pure pp
interaction (kappa =0) or a mixture of both of them (0 < kappa < 1) at a given
source of UHE cosmic neutrinos. The event rate of the GR signal against the
background is also estimated.
