@article{BoernertRinglebWilbert2018,
  author    = {Moritz B{\"o}rnert-Ringleb and J{\"u}rgen Wilbert},
  title     = {The Association of Strategy Use and Concrete-Operational Thinking in Primary School},
  journal   = {Frontiers in Education},
  volume    = {3},
  pages     = {1 -- 11},
  doi       = {10.3389/feduc.2018.00038},
  year      = {2018},
}