  Polarized parton distribution functions are determined by using asymmetry A_1
data from longitudinally polarized deep inelastic scattering experiments. From
our \chi^2 analysis, polarized u-valence, d-valence, antiquark, and gluon
distributions are obtained. We propose one set of leading-order distributions
and two sets of next-to-leading-order ones as the longitudinally-polarized
parton distribution functions.
