2Dark RG, Kaplan B, Varaklis K. Predictive value of history and physical examination in patients with suspected ectopic pregnancy [J]. Ann Emerg Med, 1999,33(3) :283-290.
1Arthur K. Au,Masashi J. Rotte,Robert J. Grzybowski,Bon S. Ku,J. Matthew Fields.Decrease in central venous catheter placement due to use of ultrasound guidance for peripheral intravenous catheters[J].American Journal of Emergency Medicine.2012(9)
