“…We point out that, apart from the aforementioned works, the existence of pulsating fronts was investigated in [43,46,54,56,58]. References [43,46,58] were also concerned with generalized transition fronts in the sense of [9,10], for which the media can be non-periodic (see [3,14,20,24,25,41,45,47,49,52] for further propagation or blocking results in non-periodic bistable media).…”