@InProceedings{vigna98:jecom,
  author = 	 {Giovanni Vigna and Luca Bonomi},
  title = 	 {{A Model-Centered Electronic Commerce Middleware}},
  booktitle = 	 {Proceedings of the International IFIP Working Conference on Trends in Electronic Commerce (TrEC)},
  year =	 1998,
  address =	 {Hamburg, Germany},
  month =	 {June}
}