Should we or shouldn't we use spoken commands in voice interfaces? - Paul Brennan; Gerhard Deffner; Debbie Lawrence; Monica Marics; Eileen C. Schwab; Marita Franzke (CHI, 1991)

Experimental evaluation of dialogue styles for hybrid telephone-based interfaces. - Donna Lauretta; Gerhard Deffner (Behav. Inf. Technol., 1996)