Chafran, Liana S Preparation of PLA blends by polycondensation of D,L-lactic acid using supported 12-tungstophosphoric acid as a heterogeneous catalyst. [electronic resource] - Heliyon May 2019 - e01810 p. digital Publication Type: Journal Article ISSN: 2405-8440 Standard No.: 10.1016/j.heliyon.2019.e01810 doi