Jianmin Xing and Rufeng Xing, Relative Injective Modules and Relative Flat Modules. journal = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology. February 2014, vol. 86(2). 365 - 372 [viewed 23 September 2024]. Available from: https://publications.waset.org/pdf/9997594.