@inproceedings {Risch93c,
author = {V. Risch},
title = {Analytic Tableaux for Default Logics},
booktitle = {Fall Symposium Series AAAI},
address = {Sheraton Imperial Convention Center, Raleigh North-Carolina, USA},
month = {october 22--24},
year = {1993},
pages = {149--155}
}