@conference {,
	title = {Testing an Ultrasonic Local Positioning System for 3D Spaces},
	booktitle = {International Conference on Indoor Positioning and Indoor Navigation (IPIN 2018).},
	year = {2018},
	month = {09/2018},
	pages = {1-4},
	publisher = {IPIN},
	organization = {IPIN},
	address = {Nantes, Francia},
	author = {K. Mannay and Ure{\~n}a, J. and A. Hernandez and J. M. Villadangos}
}
