2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/112494Gauge invariance constraints and analytical properties of the amplitudes e+ e- -> gamma-pi-pi and phi(1020) -> gamma-pi-pi are discussed in line with the criticism of N.N. Achasov in hep-ph/0606003. I show that the formulae of our paper (Yad. Fiz. {\bf 68} 1614 (2005) [PAN {\bf 68} 1554 (2005)], hep-ph/0403123) have nothing common with those N.N. Achasov claims to be ours - his criticism is therefore misplaced.14 pagesHigh Energy Physics - Phenomenologytext