Konstantinos A. Skalomenos. Discussion on 1) “Dynamic response of a finite beam resting on a Winkler foundation to a load moving on its surface with variable speed” by ND Beskou and MV Muho [Soil Dyn. Earthq. Eng. 109(2018), 222-226] and 2) “Dynamic response of an infinite beam rest. Soil Dynamics and Earthquake Engineering. 2018. 115. 935