Survey of experts on therapeutic policies and proposals for the optimal timing for allogeneic peripheral blood stem cell transplantation in transfusion-dependent patients with myelodysplastic syndrome-refractory anemia - Sohn, Sang Kyun (Korean Society of Hematology; Korean Society of Blood and Marrow Transplantation; Korean Society of Pediatric Hematology-Oncology; Korean Society on Thrombosis and Hemostasis, 2016)