\input zb-basic
\input zb-ioport
\iteman{io-port 03706249}
\itemau{Himmelblau, D.M.; Lindsay, J.W.}
\itemti{An evaluation of subsitute methods for derivatives in unconstrained optimization.}
\itemso{Oper. Res. 28, 668-686 (1980).}
\itemcc{}
\itemut{evaluation of substitute methods; derivatives; unconstrained optimization; finite difference approximations; test problems; comparison of algorithms; numerical study}
\itemli{doi:10.1287/opre.28.3.668}
\end