Contribution to the theoretical and experimental study of the dielectric material Rb0.7(NH4)0.3HSO4 H. Smaoui, H. Guermazi, Y. Mlik and T. Mhiri Eur. Phys. J. AP, 11 2 (2000) 83-89 Published online: 15 August 2000 DOI: 10.1051/epjap:2000147