J. Mędrala-Sowa, E. Perez del Rio, and P. Moskal, “Mirror Matter: Towards Precise Measurement of Ortho-Positronium Lifetime”, Acta Phys. Pol. A, vol. 148, no. 6, p. S101, Dec. 2025, doi: 10.12693/APhysPolA.148.S101.