1. D. B. Ion, JIRN Preprint, E2-7732, Dubna (1974).
2. D. B. Ion, F. G. Nichitiu, and A. C. Mihul, JINR Preprint E2-7961, Dubna (1974).
3. S. Almehed and C. Lovelace, CERN, TH-1403
4. New πN phase-shift analysis
5. Constraints on spin rotation parameters due to isospin conservation