Giridhar Pemmasani Hai-Feng Guo Yifei Dong C. R. Ramakrishnan I. V. Ramakrishnan Online Justification for Tabled Logic Programs. 24-38 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2998&spage=24 2004 conf/flops/2004 FLOPS db/conf/flops/flops2004.html#PemmasaniGDRR04