@Article{thielscher:AMAI95,
  author = 	"Steffen H{\"o}lldobler and Michael Thielscher",
  title = 	"Computing {C}hange and {S}pecificity with
		 {E}quational {L}ogic {P}rograms",
  journal = 	"Annals of Mathematics and Artificial Intelligence",
  year = 	"1995",
  volume = 	"14",
  number = 	"1",
  pages = 	"99--133"
}