Hyperelastic modeling of a materiall

[icw2250]

Hello

I'm looking for a model of a material named "TangoBlack Fullcure 930" (a rapid prototyping material).
The main problem is that I don't have a lot of data about it (Tensile strenght, elongation at break, modulus of elasticity...).
Anyway, I found two papers on the internet from people who did some tests on the material (I attach them to this post).
Here is my problem :
For the first model : C10 = 6.7664 e-2 MPa and C01 = -9.1133 e-2 MPa. The other model is C10 = 9.1054 e-2 MPa and C01 = 5.3337 e-3 MPa.
In the first model, the sum of C01 and C10 is negative, so my simulation tools doesn't accept those parameters !
The second models seems to be working but it doesn't correspond to the experimental data from the first model...

Could you help me figuring the right model for this material ?

Thank you !