On the motion under focal attraction in a rotating medium
  New results are established here on the phase portraits and bifurcations of the kinematic model in a system of ODE's, first presented by H.K. Wilson in his 1971 book, and by him attributed to L. Markus (unpublished). A new, self-sufficient, study which extends Wilson's result and allows an essential conclusion for the applicability of the model is reported here. 
Jorge Sotomayor