Spline in Parametric 3.0

Hi,

I'm working on some project and I'm using CREO parametric 3.0. I'm having a problem to identify the spline method implemented in Parametric 3.0. Which type of spline equation used in CREO? Is it NURBS or B-Spline curved equation or other type of spline curves?. Does anyone know or perhaps give me the link to answer this question?

thank you in advance.

regards.