The [1,2] Pad\'e Amplitudes for $\pi\pi$ Scatterings in Chiral   Perturbation Theory
  A detailed analysis to the [1,2] Pad\'e approximation to the $\pi\pi$ scattering 2--loop amplitudes in chiral perturbation theory is made. 
Guang-You Qin, W. Z. Deng, Z. G. Xiao and H. Q. Zheng