The Investigation of Oil Yield of Three Varieties of Black Seed (Nigella Sativa) in Different Plant Densities Journal title: International journal of Advanced Biological and Biomedical Research Authors: Esmaeil Gholinezhad| Assistant Professor, Department of agronomy, Payame Noor University. Tehran, Ir... Subject(s): Biological Sciences, Biochemistry, Microbiology, Molecular Biology, Anatomy, Physiology