“…This inequality has been studied by several mathematicians, and several related inequalities have been investigated. For example its generalizations were published by Beesack in 1962 and1971 [3,5], Hua in 1965 [17], Redheffer in 1966 [30], Calvert in 1967 [8], Godunova and Levin in 1967 [13], Maroni in 1967 [22], Boyd and Wong in 1967 [7], Beesack and Das in 1968 [4], Boyd in 1969 [6], Rozanova in 1972 [31], Vrǎnceanu in 1973 [35], Shum in 1974 and1975 [32,33], Hou in 1979 [16], G. Milovanovic and I. Milovanovic in 1980 [23], Lee in 1980 [20], He and Wang in 1981 [14], Yang in 1966 and1983 [37,38], Hong, Yang, and Du in 1982 [15], Lin and Yang in 1985 [21], Qi in 1985 [29], Imoru in 1985 and1986 [9,10], Pachpatte in 1986 and1993 [26,27], Mitrinović and Pečarić in 1988 [24], Hwang and Yang in 1990 [18], and Sinnamon in 1991…”