According to Cite Them Right (12th edition) the advice for referencing a journal article is to ensure that you provide enough bibliographic information, such as: author(s); date; article title; journal title; volume/part/issue and page numbers, so that the original source can be easily located by the person reading your work.
For journal articles the best option is to provide a doi (digital object identifier) if available.
A URL can also be used if there is no doi, or if some of the bibliographic details mentioned above are missing.
As long as you have provided enough information for the original article to be located then you do not have to include the date that you accessed the journal article.
The doi should be in this format:
https://doi.org/10.1038/s41558-020-00952-0
Many journals have both print and online equivalents. Reference the version that you have used.
As long as the reference provides enough bibliographic information to allow it to be located by the reader then additional elements, such as [Online] or database title should not be included.
However, the URL or DOI must be included when referencing an article that is only available online (as in the example below).
Culloty, E., Murphy, P., Brereton, P., Suiter, J., Smeaton, A. and Zhang, D. (2019) ‘Researching visual representations of climate change’, Environmental Communication, 13(2), pp. 179-191. https://doi.org/10.1080/17524032.2018.1533877
The following example does not have an author (note that the entry in the reference list begins with the article title) and also uses the url as there is no doi available:
'Climate Change Could Be Newest Social Determinant of Health’ (2023) Hospital Case Management, 31(7), pp. 1–16. Available at: https://search.ebscohost.com/login.aspx?direct=true&db=cul&AN=164222276&site=ehost-live (Accessed: 31 July 2023).
Section G2.1 in CTR Harvard 12th edn.
If the article is accessed online then either the DOI or Available at: URL (Accessed: date) must be included (as in the example below).
Nunez, C. (2019) ‘What is global warming, explained’, National Geographic, (January). Available at: https://www.nationalgeographic.com/environment/global-warming/global-warming-overview/ (Accessed: 21 April 2020).
Section G2.6 in CTR Harvard 12th edn.
Where the author (byline) of a newspaper article is identified then the name should be the first element in the reference (as in the example below). If there is no identified author then the reference should begin with the title of the newspaper in italics followed by the year of publication within round brackets. If accessed online either the DOI or Available at: URL (Accessed: date) should be included (as in the example below).
Harvey, F. (2020) ‘Tropical forests losing their ability to absorb carbon, study finds’, The Guardian, 4 March. Available at: https://www.theguardian.com/environment/2020/mar/04/tropical-forests-losing-their-ability-to-absorb-carbon-study-finds (Accessed: 21 April 2020).
Section G2.7 in CTR Harvard 12th edn.
Friends of the Earth Scotland (2019) UN climate negotiations confirmed for Glasgow in 2020 [Press release]. 10 September. Available at: https://foe.scot/press-release/un-climate-negotiations-confirmed-glasgow-2020/ (Accessed: 23 July 2020).
Section G2.8 in CTR Harvard 12th edn.