“…Indeed, these effects turned out to be ubiquitous in heavy-ion collisions, ranging from SIS beam energies [6,7,8], to AGS [9,10], SPS [11], and even up to RHIC energies, as discussed in an extensive report [10]. The early theoretical work done to interpret the Bevalac data [4,5] was taken up again as the SIS, AGS, and SPS results became available [12,13,14,15,16]. In particular at low bombarding energies, the π − /π + ratio is expected to provide information on the symmetry term of the nuclear equation of state [17], thus requiring the Coulomb effect to be under full control [18].…”