@article{{MaP}{}, author = {Hoi, D.}, title = { On the set of periods for periodic solusions of some linear differential equations on the multidimensional sphere Sn}, journal = {VNU Journal of Science: Mathematics - Physics}, volume = {25}, number = {3}, year = {2009}, url = {https://js.vnu.edu.vn/MaP/article/view/2647} }