O241.8
张谋.关于微分方程x=p(y)—F(x) y=Q(x, y)及x=P(y)—F(x, y) y=Q(x, y)的极限环的存在性[J].土木与环境工程学报(中英文),1994,16(4):101-104.[J]. JOURNAL OF CIVIL AND ENVIRONMENTAL ENGINEERING,1994,16(4):101-104.10.11835/j. issn.1674-4764.1994.04.015