@article{p.buttolo1997,
	author="P. Buttolo and R. Oboe and B. Hannaford",
	title="Force feedback in shared haptic virtual environments",
	journal="computers & graphics",
	year="1997",
	pages="421-429",
	volume="vol.21n.4",
	issn="0097-8493",
	note="Great Britain"
}