Convincing evidence for the Halperin-Lubensky-Ma effect at the N-SmA transition in alkyloxycyanobiphenyl binary mixtures via a high-resolution birefringence studyM. C. Cetinkaya, S. Ustunel, H. Ozbek, S. Yildiz and J. ThoenEur. Phys. J. E, 41 10 (2018) 129DOI: https://doi.org/10.1140/epje/i2018-11738-0