1. Gladman, D. D., Antoni, C., Mease, P., Clegg, D. O. & Nash, P. Psoriatic arthritis: epidemiology, clinical features, course, and outcome. Ann. Rheum. Dis. 64, (Suppl. 2), ii14–ii17 (2005).
2. Scarpa, R. et al. Microscopic inflammatory changes in colon of patients with both active psoriasis and psoriatic arthritis without bowel symptoms. J. Rheumatol. 27, 1241–1246 (2000).
3. Queiro, R. et al. Clinical features and predictive factors in psoriatic arthritis-related uveitis. Semin. Arthritis Rheum. 31, 264–270 (2002).
4. Mallbris, L., Ritchlin, C. T. & Ståhle, M. Metabolic disorders in patients with psoriasis and psoriatic arthritis. Curr. Rheumatol. Rep. 8, 355–363 (2006).
5. Scarpa, R., Ayala, F., Caporaso, N. & Olivieri, I. Psoriasis, psoriatic arthritis, or psoriatic disease? J. Rheumatol. 33, 210–212 (2006).