Bax A, Ikura M (May 1991). "An efficient 3D NMR technique for correlating the proton and 15N backbone amide resonances with the alpha-carbon of the preceding residue in uniformly 15N/13C enriched proteins". J. Biomol. NMR. 1 (1): 99–104. doi : 10.1007/BF01874573. PMID 1668719.