TransportDB: a relational database of cellular membrane transport systems. - Qinghu Ren; Katherine H. Kang; Ian T. Paulsen (Nucleic Acids Res., 2004)

Comparative Analyses of Fundamental Differences in Membrane Transport Capabilities in Prokaryotes and Eukaryotes. - Qinghu Ren; Ian T. Paulsen (PLoS Comput. Biol., 2005)

TransportDB: a comprehensive database resource for cytoplasmic membrane transport systems and outer membrane channels. - Qinghu Ren; Kaixi Chen; Ian T. Paulsen (Nucleic Acids Res., 2007)