We introduce a class of extended strict feedback nonlinear systems in which unmeasured states enter the system equations in a linear (affine) fashion. For such systems, we present a procedure for constructing dynamic partial state feedback controllers that achieve the global asymptotic tracking of given reference trajectories while maintaining internal boundedness. The controller dynamic order is equal to the number of unmeasured states. To illustrate our design procedure, we construct such a tracking controller for a nonlinear electromechanical rotor/platform system.