Towards equation of state of dark energy from quasar monitoring: Reverberation strategyB. Czerny, K. Hryniewicz, I. Maity, A. Schwarzenberg-Czerny, P. T. Życki and M. BilickiA&A, 556 (2013) A97DOI: https://doi.org/10.1051/0004-6361/201220832