International Workshop on Advanced Research in Geographic Information Systems Ascona, Switzerland, & Nievergelt, J. (1994). IGIS '94-- geographic information systems: International Workshop on Advanced Research in Geographic Information Systems, Monte Verita, Ascona, Switzerland, February/March, 1994 : proceedings. Springer-Verlag.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रInternational Workshop on Advanced Research in Geographic Information Systems Ascona, Switzerland, और Jurg Nievergelt. IGIS '94-- Geographic Information Systems: International Workshop on Advanced Research in Geographic Information Systems, Monte Verita, Ascona, Switzerland, February/March, 1994 : Proceedings. Berlin: Springer-Verlag, 1994.
एमएलए (9वां संस्करण) प्रशस्ति पत्रInternational Workshop on Advanced Research in Geographic Information Systems Ascona, Switzerland, और Jurg Nievergelt. IGIS '94-- Geographic Information Systems: International Workshop on Advanced Research in Geographic Information Systems, Monte Verita, Ascona, Switzerland, February/March, 1994 : Proceedings. Springer-Verlag, 1994.