1. Cervera R, Khamashta MA, Font J, et al. Systemic lupus erythematosus: clinical and immunologic patterns of disease expression in a cohort of 1000 patients. Medicine (Baltimore) 1993;72:113–124.
2. Perez-Vazquez ME, Villa A, Drenkard C, Cabiedes J, Alarcon-Segovia D. Influence of disease duration, continued follow up and further antiphopholipid testing on the frequency and classi fication category of antiphospholipid syndrome in a cohort of patients with SLE. J Rheumatol 1993;20:437–442.
3. Cervera R, Piette JC, Font J, et al. Antiphospholipid syndrome. Clinical and immunologic manifestations and patterns of disease expression in a cohort of 1000 patients. Arthritis Rheum 2002;46:1019–1027.
4. Wilson WA, Gharavi AE, Koike T, et al. International consensus statement on preliminary classification criteria for definite antiphospholipid syndrome. Report of an International Workshop. Arthritis Rheum 1999;42:1309–1311.
5. Lockshin MD, Sammaritano LR, Schwartzman S. Validation of the Sapporo criteria for the antiphospholipid syndrome. Arthritis Rheum 2000;43:440–443.