“…In the finite-dimensional case, various necessary, sufficient, implicit, and explicit estimates of the critical coupling strength K critical have been proposed (Hemmen and Wreszinski, 1993;Aeyels and Rogge, 2004;Jadbabaie et al, 2004;Acebrón et al, 2005;Mirollo and Strogatz, 2005;De Smet and Aeyels, 2007;Chopra and Spong, 2009;Mason, 2008, 2009;Chung and Slotine, 2010;Ha et al, 2010a;Choi et al, 2011a;Franci et al, 2011;Bullo, 2011, 2012b;Schmidt et al, 2012). We refer to (Dörfler and Bullo, 2011) for a comprehensive historical overview and present only the best known results here.…”