Pion condensation of quark matter in a static Einstein universeD. Ebert, K. G. Klimenko, A. V. Tyukov and V. C. ZhukovskyEur. Phys. J. C, 58 1 (2008) 57-68DOI: https://doi.org/10.1140/epjc/s10052-008-0667-6