Gregory P.Prastacos, an early pioneer in this realm of operation research, provided in his paper
(Prastacos 1984) a thorough, comprehensive explanation for the different stages of a blood supply chain; starting with blood collection either at the hospital itself or at donation points that feed a regional blood bank. Both the hospital and regional blood bank are stages within the decision-making pyramid, the following third level of this hierarchy would be the inter-regional blood centre which handles the coordination between several regional centres while also supervising the national blood program
(Prastacos 1984).