@book { SustainableSoilManagementoftheDrylandSoilsinNorthernNigeria,
    title = "Sustainable Soil Management of the Dryland Soils in Northern Nigeria",
    author = "Suleiman {Usman}",
    year = "2011",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783640921041",
    url = "https://www.hausarbeiten.de/document/172291"
}