APA (7th ed.) Citation

(1971). The class is happy (1. publ.). Educational Publ. Bureau.

Chicago Style (17th ed.) Citation

The Class Is Happy. 1. publ. Singapore: Educational Publ. Bureau, 1971.

MLA (9th ed.) Citation

The Class Is Happy. 1. publ. Educational Publ. Bureau, 1971.

Warning: These citations may not always be 100% accurate.