  We study the vector-boson production processes e+e- --> WWZ and e+e-
-->WWgamma which are directly affected by the trilinear and quadrilinear self
couplings of the W, Z and gamma. Our analysis is based upon a single-parameter
effective-Lagrangian model for these self interactions which contains the
standard model as a special case. Consequences for the phenomenology at an e+e-
collider of 500 GeV (NLC) are discussed, and fits of the free parameter around
its standard model value are carried out.
