Natural Language Engineering has contents of Special Issue on Interactive Question Answering available for free:

Introduction
	Special issue on interactive question answering: Introduction N. WEBB and B. WEBBER Natural Language Engineering , Volume 15, Special Issue 01, January 2009, pp 1-8 doi:10.1017/S1351324908004877 (About doi), Published Online by Cambridge University Press 22 Oct 2008 Preview Abstract PDF (99 KB) HTML (39 KB) Request Permissions Abstract HTML Article Structure Figures and Tables References
	Papers
	Interactive question answering and constraint relaxation in spoken dialogue systems S. VARGES, F. WENG and H. PON-BARRY Natural Language Engineering , Volume 15, Special Issue 01, January 2009, pp 9-30 doi:10.1017/S1351324908004889 (About doi), Published Online by Cambridge University Press 06 Nov 2008 Preview Abstract PDF (691 KB) HTML (586 KB) Request Permissions Abstract HTML Article Structure Figures and Tables References
	HITIQA: High-quality intelligence through interactive question answering S. SMALL and T. STRZALKOWSKI Natural Language Engineering , Volume 15, Special Issue 01, January 2009, pp 31-54 doi:10.1017/S1351324908004890 (About doi), Published Online by Cambridge University Press 06 Nov 2008 Preview Abstract PDF (1.374 MB) HTML (1016 KB) Request Permissions Abstract HTML Article Structure Figures and Tables References
	Does this list contain what you were searching for? Learning adaptive dialogue strategies for interactive question answering V. RIESER and O. LEMON Natural Language Engineering , Volume 15, Special Issue 01, January 2009, pp 55-72 doi:10.1017/S1351324908004907 (About doi), Published Online by Cambridge University Press 22 Oct 2008 Preview Abstract PDF (374 KB) HTML (290 KB) Request Permissions Abstract HTML Article Structure Figures and Tables References
	Designing an interactive open-domain question answering system S. QUARTERONI and S. MANANDHAR Natural Language Engineering , Volume 15, Special Issue 01, January 2009, pp 73-95 doi:10.1017/S1351324908004919 (About doi), Published Online by Cambridge University Press 28 Oct 2008 Preview Abstract PDF (478 KB) HTML (357 KB) Request Permissions Abstract HTML Article Structure Figures and Tables References
	Follow-up question handling in the IMIX and Ritel systems: A comparative study B. W. VAN SCHOOTEN, R. OP DEN AKKER, S. ROSSET, O. GALIBERT, A. MAX and G. ILLOUZ Natural Language Engineering , Volume 15, Special Issue 01, January 2009, pp 97-118 doi:10.1017/S1351324908004920 (About doi), Published Online by Cambridge University Press 24 Oct 2008 Preview Abstract PDF (198 KB) HTML (251 KB) Request Permissions Abstract HTML Article Structure Figures and Tables References
	Questionnaires for eliciting evaluation data from users of interactive question answering systems D. KELLY, P. B. KANTOR, E. L. MORSE, J. SCHOLTZ and Y. SUN Natural Language Engineering , Volume 15, Special Issue 01, January 2009, pp 119-141 doi:10.1017/S1351324908004932 (About doi), Published Online by Cambridge University Press 06 Nov 2008 Preview Abstract PDF (847 KB) HTML (970 KB) Request Permissions Abstract HTML Article Structure Figures and Tables References
	Adding semantic roles to the Chinese Treebank NIANWEN XUE and MARTHA PALMER Natural Language Engineering , Volume 15, Special Issue 01, January 2009, pp 143-172 doi:10.1017/S1351324908004865 (About doi), Published Online by Cambridge University Press 24 Oct 2008 Preview Abstract PDF (395 KB) HTML (1.187 MB) Request Permissions