NLP applied to occupational health: MEDDOPROF shared task at IberLEF 2021 on automatic recognition, classification and normalization of professions and occupations from medical texts - Lima-López, Salvador; Farré-Maduell, Eulàlia; Miranda-Escalada, Antonio; Brivá-Iglesias, Vicent; Krallinger, Martin (Procesamiento del Lenguaje Natural, 2021)