title: Controversy about ultrahard nanotwinned cBN.
authors.affiliation: Material Physics and Technology at Extreme Conditions, Laboratory of Crystallography, University of Bayreuth, 95440 Bayreuth, Germany.
authors.forename: Natalia
authors.initials: N
authors.lastname: Dubrovinskaia
authors.forename: Leonid
authors.initials: L
authors.lastname: Dubrovinsky