The nature of fifty Palermo Swift-BAT hard X-ray objects through optical spectroscopy
Proceedings article published in 2017 by
A.~F Rojas,
N. Masetti,
D. Minniti,
E. Jiménez-Bailón,
Chavushyan 
,
G. Hau,
V.~A McBride,
L. Bassani,
A. Bazzano,
A.~J Bird,
G. Galaz,
I. Gavignaud,
R. Landi,
A. Malizia,
L. Morelli
and other authors.
,
G. Hau,
V.~A McBride,
L. Bassani,
A. Bazzano,
A.~J Bird,
G. Galaz,
I. Gavignaud,
R. Landi,
A. Malizia,
L. Morelli
and other authors.
