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In this note we comment on two recently published papers by G. Valent: The1st is the preprint "On a Class of Integrable Systems with a quartic FirstIntegral, arXiv:1304.5859. April 22, (2013)". We show that the two integrableHamiltonian systems introduced in this reprint as original results are not new.They are special cases of two systems introduced by the present author in 2006in two papers [6] and [5]. The second paper is "On a Class of IntegrableSystems with a Cubic First Integral, Commun. Math. Phys. 299, 631{649 (2010),In that paper two integrable Hamiltonian systems admitting a cubic integralwere introduced. Those systems were referred to as original results by Tsiganovin [12], Vershilov and Tsiganov in [13], Bialy and Mironov in [15] and byGibbons et al in [14]. We show that those systems are not new. Both can beobtained as special cases of one system introduced by us in [4] (2002) and oneof them is a special case of a much earlier version [1] published 24 yearsearlier.

Comments on two papers by Galliano Valent, concerning integrable Hamiltonian systems admitting quartic and cubic integrals