13C NMR Determination of the Tautomeric and Ionization States of Folate in Its Complexes with Lactobacillus casei Dihydrofolate Reductase - Cheung, H. T.A.; Birdsall, B.; Frenkiel, Thomas A.; Chau, D. D.; Feeney, J. (Biological Magnetic Resonance Bank, 1995)