1. R. E. Allen and S. Lidström, Phys. Scr. 92, 012501 (2017).
2. G. E. Volovik, J. Low Temp. Phys. 202, 11 (2021).
3. S. Weinberg, Rev. Mod. Phys. 61, 1 (1989).
4. J. D. Bjorken, Report on The Dark Energy Problem: Methods and Mindsets, March 2011.
5. A. A. Abrikosov, L. P. Gor’kov, and I. E. Dzyaloshinski, Methods of Quantum Field Theory in Statistical Physics,
Dover Books on Physics (Dover, New York, 1975).