TY - JOUR A1 - Varea, C. A1 - Bernis, C. A1 - González, A. T1 - Maternal characteristics and temporal trends in birth outcomes: Comparison between Spanish and migrant mothers Y1 - 2012 DO - 10.1155/2012/412680 JF - International Journal of Population Research VL - 2012 IS - ID 412680 ER -