A blue phase with negative dielectric anisotropy in an electric field. Statics and dynamics
H.-S. Kitzerow, P.P. Crooker, S.L. Kwok, G. Heppke, Journal de Physique 51 (1990) 1303–1312.

First optical observation of Kossel diagrams in chiral smectic phases
H.-S. Kitzerow, G. Heppke, H. Schmid, B. Jérôme, P. Pieranski, Journal de Physique 51 (1990) 2087–2099.

Electrostriction of the cholesteric blue phases BPI and BPII in mixtures with positive dielectric anisotropy
G. Heppke, B. Jérôme, H.-S. Kitzerow, P. Pieranski, Journal de Physique 50 (1989) 2991–2998.

Electrostriction of BPI and BPII for blue phase systems with negative dielectric anisotropy
G. Heppke, B. Jérôme, H.-S. Kitzerow, P. Pieranski, Journal de Physique 50 (1989) 549–562.