Vogel, Stephan E., Trent Haigh, Gerrit Sommerauer, Melanie Spindler, Clemens Brunner, Ian M. Lyons, and Roland H. Grabner. 2017. “Processing the Order of Symbolic Numbers: A Reliable and Unique Predictor of Arithmetic Fluency”. Journal of Numerical Cognition 3 (2), 288-308. https://doi.org/10.5964/jnc.v3i2.55.