@proceedings{gwehenberger2007the,
  title = {The Sustainable Process Index SPI as an engineer’s tool for environmental impact assessment of processes: the sugar industry as a case study}
  author = {Gwehenberger, G.; Narodoslawsky, M.},
  publisher = {Factor X: Challenges, Implementation Strategies and Examples for a Sustainable Use of Natural Resources},
  url = {http://library.witpress.com/viewpaper.asp?pcode=SDP07-032-1},
  doi = {10.2495/SDP070321},
  year = {2007}
}