ON A CONDITION FOR A CENTER OF CUBIC NON-AUTONOMOUS EQUATIONS

[1] NONAUTONOMOUS EQUATIONS RELATED TO POLYNOMIAL TWO-DIMENSIONAL SYSTEMS [J]. PROCEEDINGS OF THE ROYAL SOCIETY OF EDINBURGH SECTION A-MATHEMATICS, 1987, 105 : 129 - 152

[2] Archbold J. W., 1970, ALGEBRA

[3] A SURVEY OF QUADRATIC SYSTEMS [J]. JOURNAL OF DIFFERENTIAL EQUATIONS, 1966, 2 (03) : 293 - &

[4] Lloyd N. G., 1988, NEW DIRECTIONS DYNAM

[5] LLOYD NG, 1982, LECT NOTES MATH, V1032, P346

[1] NONAUTONOMOUS EQUATIONS RELATED TO POLYNOMIAL TWO-DIMENSIONAL SYSTEMS [J]. PROCEEDINGS OF THE ROYAL SOCIETY OF EDINBURGH SECTION A-MATHEMATICS, 1987, 105 : 129 - 152

[2] Archbold J. W., 1970, ALGEBRA

[3] A SURVEY OF QUADRATIC SYSTEMS [J]. JOURNAL OF DIFFERENTIAL EQUATIONS, 1966, 2 (03) : 293 - &

[4] Lloyd N. G., 1988, NEW DIRECTIONS DYNAM

[5] LLOYD NG, 1982, LECT NOTES MATH, V1032, P346