Carine El Kassis José Picheral Gilles Fleury Chafic Mokbel Direction of Arrival Estimation using EM-ESPRIT with Nonuniform Arrays. 1787-1807 2012 31 Circuits Syst. Signal Process. 5 https://doi.org/10.1007/s00034-012-9397-y db/journals/cssp/cssp31.html#KassisPFM12