The Delta-4 approach to dependability in open distributed computing systems. - David Powell; Gottfried Bonn; Douglas T. Seaton; Paulo Veríssimo; F. Waeselynck (FTCS, 1988)

The Delta-4 extra performance architecture (XPA). - Peter A. Barrett; Andrew M. Hilborne; Peter G. Bond; Douglas T. Seaton; Paulo Veríssimo; Luís E. T. Rodrigues; Neil A. Speirs (FTCS, 1990)