Public health services knowledge and utilization among immigrants in Greece: a cross-sectional study - Galanis, Petros; Sourtzi, Panayiota; Bellali, Thalia; Theodorou, Mamas; Karamitri, Ioanna; Siskou, Olga; Charalambous, Giorgos; Kaitelidou, Daphne (BMC Health Services Research, 2013)