Horn, S., Loewenhaupt, M., Scheuer, H., & Steglich, F. (1979). Magnetic order and crystal fields in TmAl2 and disordered (Tm, La)Al2 alloys. Journal of Magnetism and Magnetic Materials, 14(2-3), 239-240. doi:10.1016/0304-8853(79)90128-8.