Random walks and market efficiency tests: evidence on US, Chinese and European capital markets within the context of the global Covid-19 pandemic Delicado, T.N.M., Pedro, P. 2020 Oeconomia copernicana 10.24136/oc.2020.024 Team Researchers Other ResearchersView Profile Nuno Miguel Delicado Teixeira View Profile Pedro Nuno Coelho Palhão Bicho Pardal