  We give new closed and explicit formulas for "multiple zeta values" at
non-positive integers of generalized Euler-Zagier multiple zeta-functions. We
first prove these formulas for a small convenient class of these multiple
zeta-functions and then use the analyticity of the values on the parameters
defining the multiple zeta-functions to deduce the formulas in the general
case. Also, for our aim we prove an extension of "Raabe's lemma" due to E.
Friedman and A. Pereira.
