@book { RomaniaMigrationSocioeconomicTransformationandPerspectivesofRegionalDevelopment,
    title = "Romania: Migration, Socio-economic Transformation and Perspectives of Regional Development",
    author = "Wilfried {Heller}",
    year = "1989",
    publisher = "Biblion",
    address = ", Germany",
    doi = "10.3726/b12606",
    url = "https://www.peterlang.com/document/1067050"
}