On the skew Hopf bifurcation / Florian Oskar Ottokar WagenerThe discontinuous Hopf-transversal system and its geometric regularization / Xia LiuThe discontinuous Hopf-transversal system and its geometric regularization / Xia LiuSome studies in dynamical system theory: I. Volterra integral equations of convolution type, II. Hopf bifurcation and symmetry / Stephanus Antonius van GilsThe Hamiltonian Hopf bifurcation / Jan Cornelis van der MeerHopf bifurcation in host-parasitoid models / H.A. Lauwerier