1. Nuclear Export Receptors: From Importin to Exportin
Katharine S. Ullman, Maureen A. Powers, Douglass J. Forbes 
Cell 
Volume 90, Issue 6, Pages (September 1997)
DOI: /S (00)80361-X

2. Figure 1 Ran-GTP in Import and Export
RanGTP may ensure that export complexes assemble in the nucleus, while import complexes disassemble there. RanGTP is predicted to be at high concentration in the nucleus.
Cell  , DOI: ( /S (00)80361-X)

3. Figure 2 Import and Export Receptors
Import receptors are shown at the top, while export receptors are shown below (see also Table 1).
Cell  , DOI: ( /S (00)80361-X)