https://www.cambridge.org/core/journals/visual-neuroscience/article/temporal-asynchrony-interferes-with-vernier-acuity/7D9706F5E8FAEFC9DCDD570D0C59501E (Publisher version)
Wehrhahn, C., & Westheimer, G. (1993). Temporal asynchrony interferes with vernier acuity. Visual Neuroscience, 10(1), 13-19. doi:10.1017/S0952523800003187.