1. Sobotka et al(1960)
2. Biggs et al(1964)
3. Kelly and Herbert (1967) 50
4. VitaminBl, activity in red cells;Biggs, J.C.; Mason, S.L.A.; Spray, G.H.;Brit. J. Haemat,1964
5. Vitamin B12: correlation of serum concentrations and age;Boger, W.P.; Wright, L.D.; Strickland, S.C.; Gylfe, J.S.; Ciminera, J.L.;Proc. Soc. exp. Biol,1955