Coles, Lydia (1968). "A chromatographic method for the separation of branched-chain and straight-chain compounds of columns containing urea". Journal of Chromatography A. 32 (4): 657–661. doi:10.1016/S0021-9673(01)80544-6. PMID5645558.
Coles, Lydia (1968). "A chromatographic method for the separation of branched-chain and straight-chain compounds of columns containing urea". Journal of Chromatography A. 32 (4): 657–661. doi:10.1016/S0021-9673(01)80544-6. PMID5645558.