http://repository.uhamka.ac.id/id/eprint/12689/
Students’ Mathematical Thinking in Column Calculation and Algorithms
Pramudiani, Puri
http://repository.uhamka.ac.id/id/eprint/12689/1/01_A_2021_Article_Cendekia_Puri_Prof%20Tatang_Column%20Calculation.pdf