Citing Sources

Learn how to cite your sources

Table of Contents

Table of Contents

General

References in the text should be cited in one of three ways:

1. By superscript numbers, which appear outside the punctuation if the citation applies to a whole sentence or clause.

Oscillation in the reaction of benzaldehyde with oxygen was reported previously.3

2. By italic numbers in parentheses on the line of text and inside the punctuation.

The mineralization of TCE by a pure culture of a methane-oxidizing organism has been reported (6).

3. By author name and year of publication in parentheses inside the punctuation (known as author–date).

The primary structure of this enzyme has also been determined (Finnegan et al., 2004).

All References:

  • Periodical references must include the author names, abbreviated journal title, year of publication, volume number (if any), and initial page of cited article (the complete span is better). 
  • Book references must include the author or editor names, book title, publisher, city of publication, and year of publication.
  • For material other than books and journals, sufficient information must be provided so that the source can be identified and located.

Guidelines:

Cite the reference in a logical place in the sentence.

References should be numbered sequentially.  If a reference is cited more than once, it does not receive a new number, use the original reference number.  If citing more than one reference at a time, include reference numbers in increasing order separated by commas (without spaces as superscripts, with spaces on line) or use an en dash to indicate a range of three or more. 

When citing more than one reference at one place by the author–date system, list them alphabetically according to the first author’s name, followed by a comma and the year. Use a semicolon to separate individual references. When citing more than one reference by the same author at one place by the author–date system, do not repeat the name. List the name followed by the year of each of the references in ascending order; separate the years by commas. If an author has more than one reference in the same year, add lowercase letters to the years to differentiate them. 

In all three systems, the author’s name may be made part of the sentence. In such cases, in the author–date system, place only the year in parentheses.

The syntheses described by Fraser8 take advantage of carbohydrate topology.

Jensen (3) reported oscillation in the reaction of benzaldehyde with oxygen.

According to Harris (2003), drug release is controlled by varying the hydrolytic stability of the ester bond.

Whenever authors are named, if a reference has two authors, give both names joined by the word “and”. If a reference has more than two authors, give only the first name listed, followed by “et al.” Do not use a comma before et al.; always use a period after al.

Allison and Perez12

Johnson et al. (12)

(O’Brien and Alenno, 2005)

(Bachrach et al., 2004)

Periodicals

Periodicals

Author 1; Author 2; Author 3; etc. Title of Article. Journal Abbreviation Year, Volume, Inclusive Pagination.

 

Author Name

Include all author names in a reference citation. With multiple authors, separate the names from one another by semicolons. Always end the author field with a period. List the names in inverted form: surname first, then first initial, middle initial, and qualifiers (Jr., II). Some publications list the first 10 authors followed by a semicolon and et al.

Article Title

Article titles are not mandatory. Article titles are set in roman type without quotation marks and end with a period (or a question mark if that is part of the title). Capitalization follows that of the original publication or the main words are capitalized.

Journal Name

Abbreviate the journal name according to CASSI (Chemical Abstracts Service Source Index).  One-word journal names are not abbreviated (e.g., Biochemistry, Macromolecules, Nature, Science). No punctuation is added to end this field; thus, a period will be there with an abbreviation but not with a spelled-out word.

Year of Publication

 The year is set in boldface type, followed by a comma in boldface type.

Publication Volume 

The volume number is set in italic type and is separated from the pagination information by a comma, which is set in italic type.

For periodicals in which each issue begins with page 1, include issue information (either the number or the date) in the publication volume field. Issue information is set in roman type, enclosed in parentheses, and spaced from the volume number, which it directly follows.

Issue number:

Mullin, R. Chem. Eng. News 2005, 83 (42), 7.

Date of Issue: 

Mullin, R. Chem. Eng. News 2005, 83 (Oct 17), 7.

For publications that have supplements, the following form is recommended.

Taylor, C. W.; Kumar, S. Eur. J. Cancer 2005, 40 (Suppl. 1), 781. Eur. J. Anaesthesiol. 2005, 22 (Suppl. S36), 1–35.

For journals that have no volume numbers, include issue numbers, especially when the pagination of each issue begins with page 1. Use the following form. The issue number is not italicized.

Wills, M. R.; Savory, J. Lancet 1983, No. 2, 29.

Pagination

The complete page range is preferable, but initial page numbers are acceptable. In page spans, use all digits, closed up, with no commas or spaces. Some publications use article numbering, rather than page numbering, where each article starts on page 1 include the article number.

Nonscientific Magazines and Newspapers

Author 1; Author 2; Author 3; etc. Title of Article. Title of Periodical, Complete Date, Pagination.

 Give the authors’ names in inverted form ending with a period, the article title in roman type with main words capitalized and ending with a period, the full magazine title in italic type followed by a comma in italic type, the complete date of the issue (see pp 160–161 about dates) ending with a comma, and the pagination.

Books

Books

Book references must include the author or editor names, book title, publisher, city of publication, and year of publication.

Author Name

Separate the names of multiple authors by semicolons, and always end the author field with a period. List names in inverted form: surname first, then first initial, middle initial, and qualifiers (Jr., II).

 If a book has no primary authors because each chapter was written by a different author, you may place the editor names in the author name field (especially for lists in alphabetical order). Separate editor names by commas, and a period after the abbreviation Ed. or Eds. terminates the field.

Stocker, J. H., Ed. Chemistry and Science Fiction; American Chemical Society: Washington, DC, 1998. 

Chapter Title

Chapter titles are not required. Chapter titles are set in roman type and end with a period.

Puls, J.; Saake, B. Industrially Isolated Hemicelluloses. In Hemicelluloses: Science and Technology; Gatenholm, P., Tenkanen, M., Eds.; ACS Symposium Series 864; American Chemical Society: Washington, DC, 2004; pp 24–37. 

Book Title

 In general, book titles should not be abbreviated. They are set in italic type and are separated from the next field of the reference by a semicolon, which is set in italic type. The edition number (in ordinal form) and the abbreviation “ed.” follow the book title, set off by an italic comma; they are set in roman type. The edition information is separated from the next field of the reference by a semicolon.

Reagent Chemicals, 10th ed.;

When both authors and editors are given, use the word “In” (set in roman type) immediately before the title of the book to indicate that the cited authors wrote only part of the book.

Hillman, L. W. In Dye Laser Principles with Applications; Duarte, F. J., Hillman, L. W., Eds.; Academic: New York, 1990; Chapter 2. 

Editor Name 

For books with editors, list the names of the editors, after title and edition information, in inverted form, separated from one another by commas. The names are denoted as editors by including the abbreviation “Eds.” or “Ed.” after the final name. The editor field is set in roman type and ends with a semicolon (unless it is used in the author field location).

Lignocellulose Biodegradation; Saha, B. C., Hayashi, K., Eds.; ACS Symposium Series 889; American Chemical Society: Washington, DC, 2004.

The Chemistry of the Atmosphere: Oxidants and Oxidation in the Earth’s Atmosphere; Bandy, A. R., Ed.; Royal Society of Chemistry: Cambridge, U.K., 1995.

In books that have no primary authors, the names of the editors may appear in either the author name field (especially for lists in alphabetical order) or the editor name field. When the editor names appear in the author name field, they are separated by commas and the field ends with a period.

Saha, B. C., Hayashi, K., Eds.; Lignocellulose Biodegradation; ACS Symposium Series 889; American Chemical Society: Washington, DC, 2004.

Bandy, A. R., Ed. The Chemistry of the Atmosphere: Oxidants and Oxidation in the Earth’s Atmosphere; Royal Society of Chemistry: Cambridge, U.K., 1995.

Publication Information

Name of Publisher: Generally, do not abbreviate publishers’ names.

Place of Publication: For the place of publication, give the city and state for U.S. cities or the city and country for all others. 

Year of Publication: In book references, the year is set in lightface (not bold) roman type, following the place of publication. Terminate the field with a period or with a semicolon if further information is given.

Gould, S. J. The Structure of Evolutionary Theory; Belknap Press: Cambridge, MA, 2002. Kline, R. B. Principles and Practice of Structural Equation Modeling, 2nd ed.; Guilford Press: New York, 2004.

Volume Information

Include volume number and chapter number. Use the following abbreviations and spelled-out forms with the capitalization, spelling, and punctuation shown:

  • Abstract
  • No.  
  • Paper
  • Part
  • Vol. (for specific volumes, Vol. 4; Vols. 1, 2; Vols. 1 and 2; Vols. 3–5)
  • vols. (for a number of volumes, 4 vols.)

Annual Review of Physical Chemistry; Leone, S. R., McDermott, A. E., Paul, A., Eds.; Annual Reviews: Palo Alto, CA, 2005; Vol. 56.

If a volume or part number refers to the volume or part of an entire series of books, this information is placed where a series number would normally appear and not in the volume field for the specific book being cited.

Wiberg, K. In Investigations of Rates and Mechanisms of Reactions; Lewis, E. S., Ed.; Techniques of Chemistry, Vol. VI, Part I; Wiley & Sons: New York, 1974; p 764.

If the book or set of books as a whole is the reference, do not include individual volume information.

McGraw-Hill Encyclopedia of Science and Technology, 9th ed.; McGraw-Hill: New York, 2002; 20 vols.

Pagination Information

Pagination information is set in roman type and ends with a period, except when miscellaneous information follows it, in which case it should end with a semicolon (see the next section). Use the abbreviations “p” and “pp” to indicate single and multiple pages, respectively.

  • p 57
  • pp 48–51
  • pp 30, 52, 76
  • 2005; Vol. 2, p 35.
  • 2004; pp 55–61.  

If the book as a whole is the reference, page numbers need not be given.

Miscellaneous Information

If you wish to include additional information about a book that is important for the reader to know, you may add it at the end of the reference with or without parentheses, append it to the title in parentheses before the semicolon, or place it between the title and the publisher.

Series Publications

Publications such as book series that are periodical in nature but are not journals may be styled as either books or journals. 

Online

Online

Web Sites

Author (if any). Title of Site. URL (accessed Month Day, Year), other identifying information (if any).

Use the title found on the Web site itself; add the words “Home Page” for clarification when needed. Data retrieved from Internet-based databases should include a data entry number. Stand-alone databases should be cited as computer programs. 

If an article is contained within a large and complex Web site, such as that for a university or a government agency, the host organization and the relevant program or department should be identified before giving the direct URL of the article and accession date.

Online Periodicals

Based on Print Editions

Author 1; Author 2; Author 3; etc. Title of Article. Journal Abbreviation [Online] Year, Volume, Inclusive pagination or other identifying information. URL (accessed Month Day, Year).

Online Only

Author 1; Author 2; Author 3; etc. Title of Article. Journal Abbreviation [Online] Year, Volume, Article Number or other identifying information. URL (accessed Month Day, Year).

Online Books

Without Editors

Author 1; Author 2; Author 3; etc. Book Title [Online]; Series Information (if any); Publisher: Place of Publication, Year; Volume Number, Pagination. URL (accessed Month Day, Year).

 With Editors

Author 1; Author 2; Author 3; etc. Chapter Title. In Book Title [Online]; Editor 1, Editor 2, etc., Eds.; Series Information (if any); Publisher: Place of Publication, Year; Volume Number, Pagination. URL (accessed Month Day, Year).

Computer Program

References to computer programs must be treated on a case-by-case basis. Five common presentations of computer programs are possible:

1. Book format, with the name of the program as the title

Author 1; Author 2; etc. Program Title, version or edition; Publisher: Place of Publication, Year.

2. Technical Report format

Author. Title of Report; Technical Report Number; Publisher: Place of Publication, Year; Pagination (if any).

3. CASSI format

Johnson, C. K. Oak Ridge Natl. Lab., [Rep.] ORNL (U.S.) 1978, ORNL-5348

4. Free style, as a simple listing of program title and author of program

When only minimal information (e.g., author and program name) is available, present the information as simply as possible.

Programs used in this study included local modifications of Jacobson’s ALLS, Zalkins’s FORDAP, Busing and Levy’s ORFEE, and Johnson’s ORTEP2.

5. Thesis style

Sheldrick, G. M. SHELX-76: Program for Crystal Structure Determination. Cambridge University, 1976.

Other

Presentation

References to oral presentations, posters, or demonstrations at technical meetings, possibly accompanied by handouts or brochures. These references contain no publication information.

Author 1; Author 2; Author 3; etc. Title of Presentation (if any). Presented at Conference Title, Place, Date; Paper Number.

List the data concerning the conference (name, place, and date) separated by commas and followed by a semicolon and the paper number (if any). The entire citation is set in roman type.

Zientek, K. D.; Eyler, J. R. Presented at the 51st ASMS Conference on Mass Spectrometry and Allied Topics, Montreal, Canada, June 8–12, 2003.

Dizman, B.; Elasri, M. O.; Mathias, L. J. Presented at the 227th National Meeting of the American Chemical Society, Anaheim, CA, March 28–April 1, 2004; Paper POLY 229.

Safety Data Sheets (SDS)/Material Safety Data Sheets (MSDS)

 Citations should include the title of the data sheet, which is the name of the material; the MSDS number; the manufacturing company; the location of the company; and the date on which the document was released. If the online version was used, the designation “Online” is included in brackets after the MSDS number, and the URL and date accessed are included at the end of the citation.

Hard copy (paper) MSDS

Titanium Dioxide; MSDS No. T3627; Mallinckrodt Baker: Phillipsburg, NJ, November 12, 2003.

MSDS obtained from an Internet search

Titanium Dioxide; MSDS No. T3627 [Online]; Mallinckrodt Baker: Phillipsburg, NJ, November 12, 2003.http://www.jtbaker.com/msds/englishhtml/t3627.htm (accessed 4/15/08).

MSDS obtained from a database source such as CCOHS

​Titanium Dioxide; MSDS No. T3627 [Online]; Mallinckrodt Baker: Phillipsburg, NJ, November 12, 2003. Available from Canadian Centre for Occupational Health and Safety. http://website.com (accessed 4/15/14).

Patent

Patent Owner 1; Patent Owner 2; etc. Title of Patent. Patent Number, Date.

The minimum data required for an acceptable citation are the name(s) of the patent owner(s), the patent number, and the date. Ensure that the patent stage (Patent, Patent Application, etc.) is indicated and that the pattern of the number (e.g., spaces, commas, dashes) follows that of the original patent document. 

Sheem, S. K. Low-Cost Fiber Optic Pressure Sensor. U.S. Patent 6,738,537, May 18, 2004.

Lenssen, K. C.; Jantscheff, P.; Kiedrowski, G.; Massing, U. Cationic Lipids with Serine Backbone for Transfecting Biological Molecules. Eur. Pat. Appl. 1457483, 2004.

Shimizu, Y.; Kajiyama, H. (Kanebo, Ltd., Japan; Kanebo Synthetic Fibers, Ltd.). Jpn. Kokai Tokkyo Koho JP 2004176197 A2 20040624, 2004.

Thesis

Author. Title of Thesis. Level of Thesis, Degree-Granting University, Location of University, Date of Completion.

References to theses should be as specific as practical, including, at a minimum, the degree-granting institution and date.

Chandrakanth, J. S. Effects of Ozone on the Colloidal Stability of Particles Coated with Natural Organic Matter. Ph.D. Dissertation, University of Colorado, Boulder, CO, 1994.

Mäckel, H. Capturing the Spectra of Silicon Solar Cells. Ph.D. Thesis, The Australian National University, December 2004.

Kulamer, T. M.S. Thesis, Princeton University, 2004.

Government Agencies 

Author 1; Author 2; etc. Chapter Title. Document Title; Government Publication Number; Publishing Agency: Place of Publication, Year; Pagination.

The format resembles that of a serial publication in book format. Include as much information as possible.

Gebhardt, S. E.; Thomas, R. G. Nutritive Value of Foods; Home and Garden Bulletin No. 72; U.S. Department of Agriculture, U.S. Government Printing Office: Washington, DC, 2002.

Agriculture Fact Book 2000; U.S. Department of Agriculture, U.S. Government Printing Office: Washington, DC, 2000.

Dey, A. N.; Bloom, B. Summary Health Statistics for United States Children: National Health Interview Survey, 2003; DHHS Publication PHS 2005-1551; Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Health Statistics, U.S. Government Printing Office: Washington, DC, 2005.

ISCORS Assessment of Radioactivity in Sewage Sludge: Modeling To Assess Radiation Doses; NUREG-1783; EPA 832-R-03-002A; DOE/EH-0670; ISCORS Technical Report 2004-03; Interagency Steering Committee on Radiation Standards, Sewage Sludge Subcommittee, U.S. Government Printing Office: Washington, DC, 2005.