Zuniga-Perez, J., Consonni, V., Lymperakis, L., Kong, X., Trampert, A., Fernandez-Garrido, S., et al. (2016). Polarity in GaN and ZnO: Theory, measurement, growth, and devices. Applied Physics Reviews, 3(4): 041303. doi:10.1063/1.4963919.