1. K. Nandra, X. Barcons, D. Barret, A. Fabian, J.W. den Herder, L. Piro, M. Watson et al., ATHENA Mission Proposal (2013). http://www.the-athena-x-ray-observatory.eu/images/AthenaPapers/The_Athena_Mission_Proposal.pdf. Accessed 18 Dec 2019
2. D. Barret, T. Lam Trong, J.W. den Herder, L. Piro, M. Cappi et al., in Proceedings of the SPIE 10699, 106991G (2018). https://doi.org/10.1117/12.2312409
3. C. Macculi et al., J. Low Temp. Phys. (2019) (This Special Issue)
4. S. Molendi, Exp. Astron. 44, 263 (2017). https://doi.org/10.1007/s10686-017-9544-3
5. M. Biasotti et al., J. Low Temp. Phys. (2019) (This Special Issue)