M. P. Lam, S. O. Siu, E. Lau, X. Mao, H. Z. Sun, P. C. Chiu, W. S. Yeung, D. M. Cox, and I. K. Chu. {O}nline coupling of reverse-phase and hydrophilic interaction liquid chromatography for protein and glycoprotein characterization. Anal Bioanal Chem, volume 398, issue 2, September 2010.