1. Burge, C. B., Tuschl, T. & Sharp, P. A. in The RNA World 2nd edn (eds Gesteland, R. R., Cech, T. R. & Atkins, J. F. ) 525–560 (Cold Spring Harbor Laboratory Press, 1999)
2. Will, C. L. & Lührmann, R. in The RNA World 3rd edn (eds Gesteland, R. F., Cech, T. R. & Atkins, J. F. ) 369–400 (Cold Spring Harbor Laboratory Press, 2006)
3. Yu, Y.-T., Scharl, E. C., Smith, C. M. & Steitz, J. A. in The RNA World 2nd edn (eds Gesteland, R. R.,, Cech, T. R. & Atkins, J. F. ) 487–524 (Cold Spring Harbor Laboratory Press, 1999)
4. Hinterberger, M., Pettersson, I. & Steitz, J. A. Isolation of small nuclear ribonucleoproteins containing U1, U2, U4, U5, and U6 RNAs. J. Biol. Chem. 258, 2604–2613 (1983)
5. Bringmann, P. & Lührmann, R. Purification of the individual snRNPs U1, U2, U5 and U4/U6 from HeLa cells and characterization of their protein constituents. EMBO J. 5, 3509–3516 (1986)