-The above arguments reveal that the optimal solution (...) for Model (I) by using our analytical approach is consistent with that of Sphicas [13].
-Furthermore, if (Q) is not well-defined, Johnson and Montgomery [12] propose in an intuitive way that the optimal policy is to permit no backorders (..).
-Theorem 2(B) demonstrates that their proposal is true. Also, Theorem 2(B) tells us that under this situation the better to do is to use the basic EOQ model without backorders.