An Investigation into 2, 4 Year Old Children’s Nonsymbolic Arithmetic Ability According to Task Difficulty
Korean Journal of Child Studies. 2015;36(4):229-242 
An Investigation Into 3-, 4-, and 5-Year-Old Children’s Nonsymbolic Magnitude Comparison Ability According to Ratio Limit and Task Condition
Korean Journal of Child Studies. 2017;38(1):117-126
Working Memory in Nonsymbolic Approximate Arithmetic Processing: A Dual-Task Study With Preschoolers
Cognitive Science. 2013;38(1):101-127
The effects of arithmetic task difficulty and performance level on EEG alpha asymmetry
Neuropsychologia. 1985;23(2):233-242
The Examination of 5-6 Year-Old Children’s Ability to Use Simple Maps
Journal of Education and Training Studies. 2019;7(3):182
Secretory immunoglobulin A and cardiovascular activity during mental arithmetic: effects of task difficulty and task order
Biological Psychology. 2000;52(2):127-141
Preschool Children’s Arithmetic Thinking Ability and Early Education of Mathematics
Intellectual Development and Mathematics Learning. 2023;165-194
A 14-year-old with difficulty falling asleep
Pediatric Sleep Pearls. 2017;74-77
Intuitive Nonsymbolic Arithmetic
Mathematical Cognition and Learning. 2015;201-223
Ability and Task Difficulty in Cognitive Psychology
Educational Researcher. 1981;10(1):11-21