@article{05031808, title = {Hopf bifurcation for the equation }, journal = {Divulgaciones Matem\'aticas}, volume = {13}, year = {2005}, pages = {35-43}, zbl = {1106.34047}, language = {en}, url = {http://dml.mathdoc.fr/item/05031808} }
Acosta, Antonio; Lizana, Marcos. Hopf bifurcation for the equation . Divulgaciones Matemáticas, Tome 13 (2005) pp. 35-43. http://gdmltest.u-ga.fr/item/05031808/