Liu, Chang-An, Sen Zhang, Shuai Hua, and Xin Rao. 2016. “Effects of Nitrogen and Phosphorus Fertilizer on Crop Yields in a Field Pea-Spring Wheat-Potato Rotation System With Calcareous Soil in Semi-Arid Environments”. Spanish Journal of Agricultural Research 14 (2), e1101. https://doi.org/10.5424/sjar/2016142-7347.