M. Andries, J. Paredaens, and J. den Bussche. Proc. of the Second Far-East Workshop on Future Database Systems, 3, page 276--285. Kyoto, Japan, (April 1992)
M. Andries, J. Paredaens, and J. den Bussche. Future Databases, volume 3 of Advanced Database Research and Development Series, page 276-285. World Scientific, Singapore, (1992)