APA (7e ed.) Bronvermelding

LEFFINGWELL RICHARD. (2019). BASIC MATH ADDING AND COUNTING ON (2018 Ed.). HEINEMANN LIBRARY.

Chicago (17e ed.) Bronvermelding

LEFFINGWELL RICHARD. BASIC MATH ADDING AND COUNTING ON. 2018 Ed. MINNESOTA: HEINEMANN LIBRARY, 2019.

MLA (9e ed.) Bronvermelding

LEFFINGWELL RICHARD. BASIC MATH ADDING AND COUNTING ON. 2018 Ed. HEINEMANN LIBRARY, 2019.