@conference {,
	title = {3D Position Estimation of an UAV in Indoor Environments using an Ultrasonic Local},
	booktitle = {International Conference on Indoor Positioning and Indoor Navigation (IPIN 2018)},
	year = {2018},
	month = {09/2018},
	pages = {1-8},
	publisher = {IPIN},
	organization = {IPIN},
	address = {Nantes Francia},
	author = {Gualda, D and Ure{\~n}a, J. and M.C.Perez and R. Nieto}
}
