“…In Nova´k and Tyson (2008) it is shown how even simple signalling pathways that include positive and negative feedback loops can generate complex dynamical behaviour, including toggle, amplifier, switches and oscillators. When the mathematical models include numerous equations with non-linear equations kinetics and control structures such as feedback loops, the complex dynamics of the system can only be elucidated with the support of more sophisticated tools, such as sensitivity analysis (SA) (Yue et al 2006;Joo, Plimpton, Martin, Swiler and Faulon 2007;Balsa-Canto, Alonso and Banga 2008), model reduction (Danø, Madsen, Schmidt and Cedersund 2006), and bifurcation analysis (Tyson, Csikasz-Nagy and Novak 2002;Tyson, Chen and Novak 2003;Nikolov, Vera, Rath, Kolch and Wolkenhauer 2008;Nikolov, Vera, Kotev, Wolkenhauer and Petrov 2008).…”