復(fù)數(shù)：trackballs

n.an electronic device consisting of a rotatable ball in a housing; used to position the cursor and move images on a computer screen

"a trackball is essentially an upside-down mouse"

Hingedly supported integrated trackball and selection device
Fitts' Law as a Research and Design Tool in Human-Computer Interaction
Two-handed virtual manipulation
Measuring the impact of game controllers on player experience in FPS games
Touch-sensing input devices
Carotid plaque, aging, and risk factors. A study of 457 subjects
A Taxonomy of See-Through Tools
A taxonomy of see-through tools: the video
Job demands, muscle activity and musculoskeletal symptoms in relation to work with the computer mouse.
A comparison of input devices in element pointing and dragging tasks