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.
This passage highlights the ongoing efforts to understand and refine the Chen model, which is a key concept in interest rate modeling.  The researchers are exploring its strengths and weaknesses, testing it against other models, and seeking ways to improve its accuracy and applicability.