G'day Q,
The convention I learned about quotation marks required double marks for exact quotes; one could use square brackets for inserted words of an explanatory nature and ellipses to indicate omissions. [On Mudcat many people seem to prefer italics for exact quotes and they do seem to be more easily discerned when lenghty.] Single quotation marks were used to indicate approximated quotations and/or allusions, 'so to speak'.

Best of luck with your retraining.

Cheers, Rowan