1. Biliotti, M., Jha, V., Johnson, N.L.: Foundations of Translation Planes. Monographs and Textbooks in Pure and Applied Mathematics, vol. 243, p. xvi+542. Marcel Dekker, New York (2001)
2. Cherowitzo, W.E., Johnson, N.L.: Net replacements in the Hughes–Kleinfeld semifield planes. J. Geom. 97, 45–57 (2010)
3. Cohn, P.M., Dicks, W.: On central extensions of skew fields. J. Algebra 63, 143–151 (1980)
4. Cherowitzo, W.E., Johnson, N.L., Vega, O.: $$\alpha $$-Flokki and partial$$\alpha $$-Flokki. Innov. Incid. Geom. 15, 5–29 (2017)
5. Hiramine, Y., Matsumoto, M., Oyama, T.: On some extension of 1-spread sets. Osaka J. Math. 24(1), 123–137 (1987)