@PHDTHESIS{Pankratius2007,
  author = {Victor Pankratius},
  title = {Product Lines for Digital Information Products},
  school = {University of Karlsruhe},
  year = {2007},
  address = {Karlsruhe, Germany},
  note = {Printed by Karlsruhe University Press},
  comment = {ISBN 978-3-86644-133-0},
  url = {http://www.product-lines-for-digital-information-products.com}
}