The words et al. are often used when citing references in text. An example: Smith et al. (2011) reported results from a survey of 90 residents.
The phrase is an abbreviation of the Latin words et alii or alia. Et means “and” and alii or alia means “others”. So the phrase Smith et al. means Smith and other authors and is a way of referring to additional, un-named authors of a reference.
There is no need for a full stop after et because it is not an abbreviation. Only use a full stop after al. Sometimes the words et al. are written in italics because they are Latin words, but this is becoming less common.
The words et al. should never be used in a list of references. The names of all authors of a reference should be provided in the reference list.
There are different conventions for expressing numbers in text.
Remember, the aim is to communicate clearly and make it easy for the reader to understand. It is usually easier to recognise a number when written in numerals (6, 27, 83, 214), than in words (six, twenty-seven, eighty-three, two hundred and fourteen).
I prefer to use numerals, particularly in statistical or other texts where numbers are important and frequent. In general text where numbers may not be so important or are rare, write numbers as words up to nine, then use numerals for 10 and above.
Always use numerals for measurements such as degrees, metres or kilometres, whether the measurement is written as a word (metres) or symbol (m). When a number starts a sentence, write the number in words, or rearrange the sentence.
There are many different styles for referencing material used in a publication, and for formatting reference lists. Some organisations, such as publishers, universities or government departments, have their own preferred style. Just remember the reason for including a list of references in your work is so your readers can find, read and check the original source that you found useful.
Make sure you include all the relevant details that will help someone find the same material you did.
- For websites, include the date accessed, as information can change over time as the website is updated.
- For books, include the edition of the book.
- For books, include the publisher and place of publication.
- For journal articles, include the volume number, issue number and page numbers.
If a reference is freely available on a public website, it’s helpful to include the web address of the reference (either the main site or the full location) so readers can easily access the material.