A. Anderson, N. Belnap, and J. Dunn. Princeton University Press, Princeton, NJ, (1992)With contributions by Kit Fine, Alasdair Urquhart et al,
Includes a bibliography of entailment by Robert G. Wolf.
{. Dunn, and {. Wright. Discussion paper / Centre for Economic performance Centre for Economic Performance, London School of Economics and Political Science, London, (1993)