Szukana fraza: [Abstract = "An unexpected change in demand for blood and its components probably induces a bullwhip effect, and the organizations that form the chains have to deal with supplies unreasonable in terms of their size and structure. A major role in this process is played by social networks, as a source of general mobilization among potential blood donors. Finding a way to change the relationship between social networks and the system of blood donation may minimize the disruptions occurring in the flow of blood and its components in Poland."]