This study examines Teng (2009) that was published in European Journal of Operational Research 198, 351-353 to provide a simpler solution procedure for EOQ/EPQ inventory models by using Arithmetic-Geometric-Mean inequality. We will point out Teng (2009) adopted the fill rate from Wee, Wang and Chung (2009), European Journal of Operational Research 194, 336-338 to convert two-variable minimum problems into one-variable problems. Hence, his simpler solution procedure is standing on the shoulder of a giant. There are three related papers: Cárdenas-Barrón (2010a, b) and Leung (2010) to further discussed Teng (2009). We will provide our comments on these four related papers.