\input zb-basic
\input zb-ioport
\iteman{io-port 50309100}
\itemau{Zhang, Lina; Liu, Yirong; Jiang, Xuejiao}
\itemti{The center conditions and bifurcation of limit cycles at the infinity for a cubic polynomial system}
\itemso{Applied Mathematics and Computation 218, No. 4, 1360-1370 (2011).}
\itemcc{}
\itemut{}
\itemli{doi:10.1016/j.amc.2011.06.018}
\end