When I first began to edit texts, I was puzzled by a typographical convention followed by many Danish authors. They would italicize quotations. Most would use quotation marks as well, which they would also use when block indenting quoted material. Let's review the basics.
Block indentation is used to set off long quotes. Journals and publishers differ on what to count as a long quote and they will sometimes allow some leeway for stylistic reasons. Some will say anything over 40 words should be block indented, and some, like Booth, Colomb and Williams, will say anything over three lines. Here's an example:
The Stoics were especially interested in grammatical correctness. They taught that everything should be called by its proper name and carried this to the extreme of denying that any word is in itself obscene (Cicero, To His Friends 9.22.1). They preferred a simple, straightforward style, and their definition of ornamentation is a narrow one. According to Plutarch (On the Contradictions of the Stoics 28.1047a-b), in the first book of his work on rhetoric Chrysippus required "a liberal and simple adornment of the words," while rejecting such niceties of style as avoidance of hiatus. (Kennedy 1994: 91)
While house styles again differ, most American publishers ask that you use double quotation marks to set off quotations that are "run into the text" (CMoS 11.33) and that you replace double quotation marks with single quotation marks in the quoted matter. According to George Kennedy, for example, the Stoics "taught that everything should be called by its proper name" (1991: 91). Citing Plutarch, Kennedy tells us that "Chrysippus required 'a liberal and simple adornment of the words,' while rejecting such niceties of style as avoidance of hiatus" (Kennedy 1991: 91). Notice that Kennedy's double quotes have now been replaced with single quotes.
The ASQ would ask you to put the reference right after the author name. According to George Kennedy (1991: 91), for example, the Stoics "taught that everything should be called by its proper name". Notice that the period (full stop) goes outside the quoted matter. Again, you will find some variation among publishers on this point, but normally not among those who want the reference after the quote, where it's usually close quote, reference, full stop.
In any case, before coming to Denmark I have never seen the convention of italizing whole quotations, or of setting off blockquotes with quotation marks as well. If anyone knows where these conventions came from, I'd love to hear about it. I'd also like to hear from anyone who has seen these conventions in other countries, and know when, if at all, they have been used in English.