Evolving mortality and clinical outcomes of hospitalized subjects during successive COVID-19 waves in Catalonia, Spain oleh Albert Roso-Llorach, Xavier Serra-Picamal, Francesc X. Cos, Meritxell Pallejà-Millán, Lourdes Mateu, Antoni Rosell, Benito Almirante, Jaume Ferrer, Mercè Gasa, Carlota Gudiol, Anna Maria Moreno, Jose Luís Morales-Rull, Maria Rexach, Gladis Sabater, Teresa Auguet, Francesc Vidal, Ana Lerida, Josep Rebull, Kamlesh Khunti, Josep M. Argimon, Roger Paredes