“…The previous means are mutually comparable, except U and A which are not comparable, see [7]. The two chains of inequalities H < G < L < P < A < M < T and L < V < P < U < M are well-known in the literature, see also [5,7,6]. A large number of papers concerning recent developments about the means P, T, M, U and V and their optimal bounds in terms of the other (power) standard means can be found in the literature, see for instance [13,14,15] and the related references cited therein.…”