Where to find the rtp parameters for phosphorylated residues?

Hi

I need to simulate a phosphorylated protein. I already have found information of how to introduce a phosphorylated residue in gromacs ([Add TPO, SEP to Amber99SB-ildn (ffbonded)]

However, I can not find analogous information for other phosphorylated residues. I was wondering if there is a data base o webpage where I can download such information…

Any help would be greatly appreciated

S h.v