1. Nakano, T., et al. (LEPS Collaboration): Phys. Rev. Lett. 91, 012002 (2003)
2. Diakonov, D., Petrov, V., Polyakov, M.: Z. Phys. A 359, 305 (1997)
3. A review of the events during this period together with references to the experimental work is provided in R.A. Schumacher. arXiv: nucl-ex/051204
4. McKinnon, B., et al. (CLAS Collaboration): Phys. Rev. Lett. 96, 012002 (2006), Shirotori, K., et al.: Phys. Rev. Lett. 109, 132002 (2012) and references cited therein
5. Yao, W.-M., et al. (Particle Data Group): J. Phys. G: Nucl. Part. Phys. 33, 1 (2006), see, in particular, the “Pentaquark Update” by G. Trilling on page 1019