The two oscillator circuits below are appropriate for using crystal oscillators in series or parallel mode: Modeling of nonlinear micromechanical resonators and their simulation Using the harmonic‐balance process PDF Layout of resonators to the willpower on the temperature coefficients of elastic constants of monocrystalline silicon Nd:GdVO4 has some great benefits https://www.hxcrystals.com/seokeywords/bulk-crystal-oscillator.html