@book{WalaBaumueller,
  author    = {Wala, Thomas and Baum{\"u}ller, Josef},
  title     = {Klausurtraining Investitionsrechnung : {\"U}bungsbeispiele und Wiederholungsfragen (f{\"u}r Bachelorstudierende)},
  publisher      = {Fachhochschule Technikum Wien},
  subject      = {Training},
  language  = {de}
}
@article{WalaLeutgeb,
  author    = {Wala, Thomas and Leutgeb, Daniel},
  title     = {Investitionscontrolling. Systematische Identifikation und Umsetzung von Wertsteigerungspotenzialen},
  series = {Controlling. 21-MalBindestrich-Controlling f{\"u}r die Praxis},
  journal   = {Controlling. 21-MalBindestrich-Controlling f{\"u}r die Praxis},
  editor    = {Eschenbach, Rolf and Baum{\"u}ller, Josef and Siller, Helmut},
  pages     = {247ff},
  subject      = {Investment},
  language  = {de}
}