@article{ berlage94selective,
    author = "Thomas Berlage",
    title = "A selective undo mechanism for graphical user interfaces based on command objects",
    journal = "ACM Transactions on Computer-Human Interaction",
    volume = "1",
    number = "3",
    pages = "269--294",
    year = "1994",
    url = "citeseer.ist.psu.edu/berlage94selective.html" }