VOKOUN, D., BELEGGIA, M., HELLER, L. Magnetic guns with cylindrical permanent magnets. Journal of Magnetism and Magnetic Materials. 2012, 324(9), 1715-1719. ISSN 0304-8853. E-ISSN 1873-4766. Available: https://doi.org/10.1016/j.jmmm.2011.12.026.