EP2997031A1 - PROCESS FOR THE PREPARATION OF HIGH PURITY AMORPHOUS PEMETREXED DISODIUM AND CRYSTALLINE FORMS OF N-[4-[2-(2-AMINO-4,7-DIHYDRO-4-OXO-3H-PYRROLO[2,3- D]PYRIMIDIN-5-YL)ETHYL]BENZOYL]-L-GLUTAMIC ACID