1. [1] H. Ahmad, M. Hajja, and M.-C. Kang, Rationality of some projective linear actions, J. Algebra 228 (2000), no. 2, 643–658.
2. [2] H. Brown, R. Bülow, J. Neubüser, H. Wondratschek, and H. Zassenhaus, Crystallographic Groups of Four-Dimensional Space, Wiley Monogr. Crystallogr. 5, Wiley, New York, 1978.
3. [3] H. Chu, S.-J. Hu, M.-C. Kang, and B. E. Kunyavskii, Noether’s problem and the unramified Brauer group for groups of order $64$, Int. Math. Res. Not. IMRN 2010, no. 12, 2329–2366.
4. [4] J.-L. Colliot-Thélène and J.-J. Sansuc, “The rationality problem for fields of invariants under linear algebraic groups (with special regards to the Brauer group)” in Algebraic Groups and Homogeneous Spaces, Tata Inst. Fund. Res. Stud. Math. 19, Tata Inst. Fund. Res., Mumbai, 2007, 113–186.
5. [5] P. K. Draxl, Skew Fields, London Math. Soc. Lecture Note Ser. 81, Cambridge Univ. Press, Cambridge, 1983.