# Why do open-closed cylinders resonate at high input impedance?

According to this paper, open-closed cylinders (clarinets) resonate at maxima of input impedance, while open-open cylinders (flutes) resonate at minima of impedance.

Since acoustic impedance is defined as the ratio of pressure to flow, I would naturally tend to think that resonances have to take place at minima of impedance (maxima of admittance). How is it that resonances in the clarinet take place when this is at maximum?