$D^+ \to K^- \p^+ \p^+ $: the low-energy sector
  An effective $SU(3)\times SU(3)$ chiral lagrangian, which includes scalar resonances, is used to describe the process $D^+ \rar K^- \p^+ \p^+$ at low-energies. Our main result is a set of five $S$-wave amplitudes, suited to be used in analyses of production data. 
D. R. Boito, P. C. Magalh\~aes, M. R. Robilotta and G. R. S.   Zarnauskas