1. Balogh, Z., Rohner, H.: Self-similar sets in doubling spaces. Ill. J. Math. 51(4), 1275–1297 (2007)
2. Springer Monographs in Mathematics;A. Bonfiglioli,2007
3. Capogna, L., Danielli, D., Pauls, S.D., Tyson, J.T.: An Introduction to the Heisenberg Group and the Sub-Riemannian Isoperimetric Problem. Birkhäuser, Basel (2007)
4. Mathematical Surveys and Monographs;G. David,1993
5. Lecture Notes in Mathematics;D. Deng,2009