ADONIS observations of hard X-ray emitting late B-type stars in Lindroos systems N. Huélamo, W. Brandner, A. G. A. Brown, R. Neuhäuser and H. Zinnecker A&A, 373 2 (2001) 657-664 Published online: 15 July 2001 DOI: 10.1051/0004-6361:20010690