Fig. 1

Bipartite graph between patients {α,β} and physicians {A,B,C,D}. (L) An edge between a patient and a physician means the patient visited the physician. (R) A referral path of Patient α in chronological order
Bipartite graph between patients {α,β} and physicians {A,B,C,D}. (L) An edge between a patient and a physician means the patient visited the physician. (R) A referral path of Patient α in chronological order