Acoustic attenuation study on the normal-state pseudogap in underdoped Q. M. Zhang, Y. N. Wang, A. Li, Q. Qiu, X. S. Xu, Y. Feng and L. Zhou Europhys. Lett., 47 1 (1999) 104-109 Published online: 01 September 2002 DOI: 10.1209/epl/i1999-00358-9