Menegazzi JJ, Salcido DD, Menegazzi MT, Rittenberger JC, Suffoletto BP, Logue ES, Mader TJ. Effects of an impedance threshold device on hemodynamics and restoration of spontaneous circulation in prolonged porcine ventricular fibrillation. Prehosp Emerg Care. 2007 Apr-Jun; 11(2):179-85.