Common Abbreviations in Writing

Two most common abbreviations in writing.

[Text in square brackets is word/phase being abbreviated.]

i.e. [id est]		that is

e.g. [exempli gratia]	for example

  Both abbreviations are almost always separated from text by commas.  
       "The best interpretation, i.e., my opinion, is that ..."

Abbreviations used in references.

et al. [et alia] 	and others
	
  Used when citing a list of more than three authors to 
  substitute for all the authors' names except the first.

ibid. [ibidem]          in the same place

  Refers to immediately preceding footnote

op. cit. [opere citato] in the work cited

  Examples of ibid. and op. cit.

  4. R. Poirer, "Learning physics," (Academic, New York, 1993), p. 4.
  5. Ibid, p. 9.
  6. T. Eliot, "Astrophysics," (Springer, Berlin, 1989), p. 141.
  7. Poirer, op. cit., p. 89.
  8. Eliot, op. cit., p.148.

Today, many omit op. cit. and ibid. because they add no real information.

In the case where the same author has written more than one book, use author and date -- e.g., Eliot, 1997, p. 213, to distinguish from book by the same author in (say) 1994.