1. Topological approach to investigation of acoustic
axes in
crystals,
Crystallography Reports (Kristallografiya), 2006, V.
51, no. 1, 104-109 (with B.M. Darinskii
and V.G. Zvyagin).
2. Longitudinal normals and
existence of acoustic axes in
crystals, Nonlinear
Analysis B: Real World Applications, V. 10 (2009),
798-809 (with B.M. Darinskii
and V.G. Zvyagin).