In order to simulate an oscillator using the shooting method, the period of oscillation is an unknown.  According to Kundert's paper, "Introduction to RF Simulation and Its Application", an additional equation which constrains the phase of the computed solution is required.  He then references his book, "Steady-State Methods for Simulating Analog and Microwave Circuits", for an explanation.  Unfortunately my copy is currently packed away until for several more weeks until I've completed a move.

Does anyone have a sketch for how you would formulate the phase constraint equation for the shooting method?