1. Adams, D., Hedberg, L.: Function Spaces and Potential Theory. Springer, Berlin (1996)
2. Ahmed, I., Karadzhov, G., Raza, A.: General Holmstedt’s formulae for the K-functional. J. Funct. Sp. 2017, 4958073 (2017)
3. Alvino, A.: Sulla diseguaglianza di Sobolev in spazi di Lorentz. Boll. Un. Mat. Ital. A (5) 14(1), 148–156 (1977)
4. Ariño, M.A., Muckenhoupt, B.: Maximal functions on classical Lorentz spaces and Hardy’s inequality with weights for nonincreasing functions. Trans. Am. Math. Soc. 320, 727–735 (1990)
5. Bagby, R.J., Kurtz, D.S.: Covering lemmas and the sharp function. Proc. Am. Math. Soc. 93, 291–296 (1985)