“…• reduction of purchasing related costs (namely, acquisition costs (e.g., [4,12,[15][16][17]), transaction costs (e.g., [4,[16][17][18]), administrative costs (e.g., [12,17,19,20]) • human resources savings, since some purchasing effort is transferred to the group [21,17] • increased information on supply markets [18] • increased focus on core operational activities (e.g., [17,21])…”