New Darboux Transformation for Hirota-Satsuma coupled KdV System
  A new Darboux transformation is presented for the Hirota-Satsuma coupled KdV system. It is shown that this Darboux transformation can be constructed by means of two methods: Painlev\'{e} analysis and reduction of a binary Darboux transformation. By iteration of the Darboux transformation, the Grammian type solutions are found for the coupled KdV system. 
Heng Chun Hu and Q. P. Liu