Using observational data published as phase curves of the effective magnetic field strength $B_{\rm e}(P)$ and the surface field $B_{\rm s}(P)$, magnetic models of three stars with long rotational periods are calculated by the Magnetic Charge Distribution method. For two of these stars (HD 2453 and HD 12288), the structure of the magnetic field can be described well by a central dipole model. The third star (HD 200311) is better fitted by a model of a displaced dipole, being decentered by $\triangle r = 0.08 R$ along the dipole axis.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html