Selective imaging of 3D director fields and study of defects in biaxial smectic A liquid crystals I. I. Smalyukh, R. Pratibha, N. V. Madhusudana and O. D. Lavrentovich Eur. Phys. J. E, 16 2 (2005) 179-191 Published online: 22 February 2005 DOI: 10.1140/epje/e2005-00019-8