@article{HerzogEhlertFritz2017,
  author    = {Moritz Herzog and Antje Ehlert and Annemarie Fritz},
  title     = {A Competency Model of Place Value Understanding in South African Primary School Pupils},
  journal   = {African Journal of Research in Mathematics, Science and Technology Education},
  volume    = {21},
  pages     = {37 -- 48},
  doi       = {10.1080/18117295.2017.1279453},
  year      = {2017},
}