  We have measured the ZZ-gamma and Z-gamma-gamma couplings by studying p-bar p
-> (missing ET) gamma + X events at sqrt(s)=1.8 TeV with the D0 detector at the
Fermilab Tevatron Collider. This first study of hadronic Z-gamma production in
the neutrino decay channel gives the most stringent limits on anomalous
couplings available. A fit to the transverse energy spectrum of the photon in
the candidate event sample, based on a data set corresponding to an integrated
luminosity of 13.1 pb^(-1), yields 95% CL limits on the anomalous CP-conserving
ZZ-gamma couplings of |h^Z_(30)|<0.9, |h^Z_(40)|<0.21, for a form-factor scale
Lambda = 500 GeV. Combining these results with our previous measurement using Z
-> ee and mu-mu yields the limits:|h^Z_(30)|<0.8, |h^Z_(40)|<0.19 (Lambda = 500
GeV) and |h^Z_(30)|<0.4, |h^Z_(40)|<0.06 (Lambda = 750 GeV).
