devote a paper to study and extend Chen model. Gallant et al. devote a paper to test Chen model and other models; Wibowo and Cai, among some others, devote their PhD dissertations to testing Chen model and other competing interest rate models.
Researchers have dedicated papers to studying and improving the Chen model.  Gallant et al. published a paper that tested the Chen model and other models.  Wibowo and Cai, among others, have also focused their PhD dissertations on testing the Chen model and other competing interest rate models.