“…It is easy to observe that the class 0-IFR corresponds to the class ILR (or PF, density class) (see Ross [13] for the definition), and the classes 1-IFR, 1-IFRA, 1-NBU, 1-NBUCV, 1-NBUFR, 2-IFR, 2-IFRA, 2-NBUFR, and 2-NBAFR are identical to the classes IFR, IFRA, NBU, NBU(2), NBUFR, DMRL, DMRLHA, NBUE, and HNBUE, respectively (see Deshpande et al [4]). Moreover, the classes 1-NBAFR, 3-IFR, and 1-CX are the NBAFR, DVRL, and NBUC classes, introduced by Loh [lo], by Launer [9], and by Cao and Wang [3], respectively. Details on the above-mentioned correspondences may be found in Fagiuoli and Pellerey [5] and references therein.…”