The main difference between the author–date and the notation systems is the use of a unique number for each reference in the notation system:
Author–date
In-text: The GDC considered 2012 to be a very successful year (GDC 2012).
Reference list: GDC (Grains Development Council) (2012). Annual report: 2012, GDC, Canberra.
Notation
In-text: The GDC considered 2012 to be a very successful year.1
Reference list: 1. Grains Development Council. Annual report: 2012. Canberra: GDC, 2012
Both systems have numerous variations that differ in formatting details (e.g. punctuation, use of italic and roman type, level of abbreviation of the text).
Author–date referencing
In the Harvard system, a work is cited in the text using the author name and year of publication. In the reference list, the author name and year of publication are the first 2 elements of a reference, and references are listed alphabetically by author name. A reference list may appear at the end of each chapter or section, or at the end of the whole work.
Many reference styles are based on this system, including that of the Australian Government Style manual and the American Psychological Association (APA).
The author–date style described in the Chicago manual of style is widely used in history and economics, and that of the Modern Language Association (MLA) in the arts and humanities – particularly English studies, literary studies, languages, cultural studies, drama, theatre, film and TV.
Notational referencing
In the notation system, works are referred to in the text by numbers (e.g. superscripted or bracketed) and listed sequentially by number at the end of the work or the bottom of a page. The notation system can be further divided into the Vancouver system (citation–sequence – references are numbered in the list in the order they first appear in the text; or citation–name – references in the list are numbered in alphabetical order by author) and the Oxford (documentary-note) system.
The Oxford system differs from the Vancouver system in allowing each notation to include more than 1 reference, as well as, for example, explanatory information that is not essential to the text.
Many medical journals use the Vancouver system; see the International Committee of Medical Journal Editors(Opens in a new tab/window) and the National Library of Medicine(Opens in a new tab/window) (NLM) for details.
Variations in author–date and notation systems
The order of the components of a reference, particularly of the year of publication, the punctuation between the components, and the font weight (bold, normal) and style (italic, roman) have traditionally been applied quite differently in Harvard and notation referencing systems. The table below shows the styling of a journal article using different referencing systems and styles.
| Referencing system | Styled reference | Notes |
|---|---|---|
| Harvard – Biotext style | Griffith GP, Hop H, Vihtakari M, Wold A, Kalhagen K & Wing Gabrielsen G (2019). Ecological resilience of Arctic marine food webs to climate change. Nature Climate Change 9:868–872. | All authors listed Minimal punctuation
|
| Harvard – Australian Government style manual | Griffith GP, Hop H, Vihtakari M, Wold A, Kalhagen K and Wing Gabrielsen G (2019) ‘Ecological resilience of Arctic marine food webs to climate change’, Nature Climate Change, 9:868–872. | Minimal punctuation Single quotes for article name
|
| Harvard – APA | Griffith, G.P., Hop, H., Vihtakari, M., Wold A., Kalhagen, K., & Wing Gabrielsen, G. (2019). Ecological resilience of Arctic marine food webs to climate change. Nature Climate Change, 9, 868–872. | Author names heavily punctuated
|
| Harvard – MLA | Griffith, Gary et al. “Ecological Resilience of Arctic Marine Food Webs to Climate Change.” Nature Climate Change, vol. 9, 2019, pp. 868-872. | First name in full Double quotes and maximal capitals for article title |
| Vancouver – citation–sequence – NLM | 1. Griffith GP, Hop H, Vihtakari, M, Wold A, Kalhagen K, Wing Gabrielsen G. Ecological resilience of Arctic marine food webs to climate change. Nat. Clim. Chang. 2019 Oct;9:868-72. | All authors given, or reduced to 3 or 6 followed by ‘et al’ or ‘and others’ Abbreviated journal title, roman Publication date after journal title |
| Oxford – Australian Government style manual | 1. GP Griffith, H Hop, M Vihtakari, A Wold, K Kalhagen and G Wing Gabrielsen, ‘Ecological resilience of Arctic marine food webs to climate change’, Nature Climate Change, 2019, 9:868–872. | Initial precedes family name Single quotes for article name Publication year after journal title |