APA (7e ed.) Bronvermelding

SCHULLER ROBERT H. (1991). BE HAPPY ATTITUDES: 8 POSITIVE ATTITUDES THAT CAN TRANSFORM YOUR LIFE. BANTAM BOOKS.

Chicago (17e ed.) Bronvermelding

SCHULLER ROBERT H. BE HAPPY ATTITUDES: 8 POSITIVE ATTITUDES THAT CAN TRANSFORM YOUR LIFE. NEW YORK: BANTAM BOOKS, 1991.

MLA (9e ed.) Bronvermelding

SCHULLER ROBERT H. BE HAPPY ATTITUDES: 8 POSITIVE ATTITUDES THAT CAN TRANSFORM YOUR LIFE. BANTAM BOOKS, 1991.