The Author-Page style of in-text referencing (e.g., MLA) is the default for all students in all subjects, however, for the IB Diploma programme, some departments choose a different style -- whether in-text Author-Date-Page (e.g., APA) or bottom-of-the-page Footnotes (e.g., Chicago) -- as indicated below.
MLA (Modern Language Association) -- this is the Author-Page style of inline citations
All Languages A & B, Economics, Design Technology, Film Studies, Visual Arts, Theatre, Music
(American Psychological Association) -- this is the Author-Date-Page
style of inline citations
Psychology, Environmental Systems & Society, Biology, Chemistry, Physics, Geography, Mathematics, Computer Science, World Studies
-- this is the style that uses footnotes
at the bottom of the page