@conference{GrAc07,
	author = {Eberhard Grummt and Ralf Ackermann},
	title = {Proof of Possesion: Using RFID for large-scale Authorization Management},
	year = {2007},
	editor = {Max Mühlhäuser and Alois Ferscha and Erwin Aitenbichler},
	pages = {174--182},
	address = {Springer-Verlag Berlin Heidelberg}
}