The 3-em dash followed by a full stop is used for successive entries by the same author or editor and replaces the name after the first apperance in the bibliography. 

 e.g. 

Crowley, John. E.  The invention of comfort: sensibilities and design in early modern Britain and early America.  Baltimore, Md:  Johns Hopkins University Press, 2001.

— — —.  Imperial landscapes:  Britain's global visual culture, 1745-1820.  New Haven:  Yale University Press, 2011.

Each time you use a source, whether through a direct quote or through a paraphrase or summary you must cite your source by using a Note. Notes are always listed together in sequential order at the end of the page on which the reference appears. 

Each citation consists of two parts: a superscript number in the text following the end of the sentence or clause in which the source is referenced and a corresponding full-sized number at the start of the endnote with details of the source. 

The first Note for each source should include all relevant information about the source: author’s full name, source title, and facts of publication.

If you cite a source again a second or subsequent time in the same document, the Note should only include the surname of the author, a shortened form of the title (if more than four words), and relevant page number(s). 

Short form for subsequent and consecutive citations

The short form should include enough information to remind the reader of the full title or to lead them to appropriate entry in the bibliography.

For example:

    1. Fabio Schillaci, Architectural Renderings: Construction and Design Manual (Chichester: West Sussex: Wiley, 2010), 120.

    2. Schillaci, Architectural Renderings, 251.

    3. Schillaci, 257.

    4. Richard Read, Art and its Discontents: The Early Life of Adrian Stokes (Aldershot, England: Ashgate, 2002), 65.

    5. Schillaci, Architectural Renderings, 258.

See The Chicago Manual of Style Online, Chapter 14, Section 34.

In the NB system, the bibliography provides an alphabetical list of all sources used in a given work. The bibliography, is usually placed at the end of the work and should include all sources cited within the work and may sometimes include other relevant sources that were not cited but provide further reading and act as an indication to the reader of the breadth and depth of an author's research.

All included sources (books, articles, websites, etc.) in the bibliography are arranged alphabetically by author’s last name. If no author or editor is listed, the title may be used instead.

All entries in the bibliography will include the author (or editor, compiler, translator), title, and facts of publication.

Author’s Names

The author’s name is inverted in the bibliography, that is the the last name is listed first followed by a comma and the first name.

Titles

Titles of books and journals are italicized. Titles of articles, chapters, poems, etc. are placed in quotation marks.

Publication Information

The year of publication is listed after the publisher or journal name.

Punctuation

In a bibliography, all major elements are separated by full stops.

Notes vs Bibliography

Note that this guide has given a basic overview of the formatting of the bibliography.  For more information about bibliographies (including Selected Bibliographies, Annotated Bibliographies, and Bibliographic Essays), consult Chapter 14 of The Chicago Manual of Style, 17th edition.