Seyyedi, S. M., Khajeh-Hosseini, M., Rezvani Moghaddam, P., & Shahandeh, H. "Relation between the increasing soluble phosphorus and nitrogen uptake and its effects on phosphorus harvest index of black seed", Iranian Journal of Field Crop Science, 46, 1, 2015, 25–36. doi: 10.22059/ijfcs.2015.54043