Positron annihilation in boron nitride crystals Vishnevskii, A. S. ; Dekhtyar, I. Ya. ; Madatova, E. G. ; Mikhalenkov, V. S. ; Čížek, A. Abstract Publication: Physica Status Solidi Applied Research Pub Date: October 1977 DOI: 10.1002/pssa.2210430228 Bibcode: 1977PSSAR..43..589V