APA (7th ed.) Citation

Ziegler, J. (1991). Direct manipulation techniques for human-computer interfaces.

Chicago Style (17th ed.) Citation

Ziegler, Jürgen. Direct Manipulation Techniques for Human-computer Interfaces. Stuttgart, 1991.

MLA (9th ed.) Citation

Ziegler, Jürgen. Direct Manipulation Techniques for Human-computer Interfaces. 1991.

Warning: These citations may not always be 100% accurate.