The preferred grammar and usage of the DPC is based on the Chicago Manual of Style (17th ed.), though it has some deviations. Referencing is based on the Harvard in-text (or author-date) system. This Style Guide is not exhaustive but provides basic guidelines relevant to ensuring DPC publications remain clear and consistent as possible, acknowledging that digital preservation encompasses a broad range of disciplines with different grammar and usage conventions. If an author is unsure of a point of grammar or usage, they should consult the source guidelines (mentioned above) or clarify with the DPC.   

1. Spelling

  • As a general guide to spelling, DPC prefers the first spelling given in the Oxford English Dictionary. This preference gives priority to certain norms including ‘z’ spellings (for example, ‘digitization’ not ‘digitisation’ and ‘organize’ not ‘organise’), though it provides commonly used exceptions: advertise, advise, analyse, chastise, compromise, improvise, televise. Some other preferred spellings include artefact, medieval, homogeneous, millennium.

  • Foreign place names consistently follow either the anglicized or the country of origin’s form, but not both in the same work.

2. Grammar and Usage

Abbreviations and acronyms:

  • Full stops are used for abbreviations that end in a lowercase letter: p. (page), vol., e.g., i.e., etc., a.k.a., a.m., p.m., Ms., Dr., et al. (‘et’ is not an abbreviation; ‘al.’ is).

  • Full stops are used for initials standing for given names: E. B. White; but are not used for an entire name replaced by initials: JFK.

  • There are no full stops with abbreviations that include two or more capital letters, even if the abbreviation also includes lowercase letters: VP, CEO, MD, PhD, UK, US, NY, and so on.

  • In main text, ‘for example’ and ‘such as’ are used rather than ‘e.g.’. Similarly, ‘that is’ rather than ‘i.e.’, and ‘and so on’ rather than ‘etc’ (although these may be used in tables). A comma precedes ‘e.g.’. Full stops are used in ‘i.e.’, ‘e.g.’ and ‘et al.’.

  • At the first occurrence of an acronym, the full name is spelt out, with the acronym in brackets following it. For example, the Digital Preservation Coalition (DPC). After that, the acronym is used.

  • Page numbers are indicated by ‘p.’ followed by the number for a single page, or ‘pp.’ followed by the page numbers with no space, for example pp.12-21.


  • Capitals are used sparingly. They are used for proper nouns, titles (including local or central government departments, directorates or sections), and for prefixes forming part of a compound name, such as the Archbishop of Canterbury and the Duke of Edinburgh. Where a prefix or title is used in a general sense, it is lower case, such as ‘a duke’, ‘the president’, ‘county archaeologist’, ‘member’, and so on.

  • The definite article – ‘the’ – is capitalized where it forms part of the name of an organization or institution. The definite article is also capitalized where it forms part of a title of a publication, such as The Boston Globe, or The SAGE Handbook of Social Media Research Methods.

  • Parts of geographical names are capitalized when they refer to recognized divisions of a country. For example: Northern Ireland (a political division), but northern Scotland (a general geographical description).

  • Capitals are used for names of institutions and movements, including schools of painting, so that Christianity, Buddhism, Islam, Marxism, Colourists and the Church (when it refers to the Christian Church as a whole) are capitalized.

  • Words in the titles of books or exhibitions all have initial capitals, except for words such as ‘it’, ‘and’, and so on.


  • Technology Watch Reports do not use contractions. Words like ‘it’s’ and ‘can’t’ are spelt out in full.

  • For other DPC publications, such as Guidance Notes, contractions are used if preferred by the author, as long as they are consistent. All contractions should be spelt out or all contractions should remain shortened, but not both in the same work.


  • Short quotations are incorporated into the text using single quotation marks, also called inverted commas (following the Oxford style rather than the Chicago Manual of Style). Longer quotations (usually about 100 words or more) are set off from the text by indenting or centring, without quotation marks.

  • Quotations are given exactly as they appear in the original and not altered to conform to DPC Style. If any words are added or omitted, square brackets are inserted to indicate additions, and the mark of an ellipsis (…) for omissions.

  • Some changes are permissible to make a passage fit into the syntax and typography of the surrounding text. Single quotation marks may be changed to double, and double to single. The initial letter may be changed to a capital or a lowercase letter. Obvious typographic errors may be corrected silently (without comment).

  • Direct quotations are always indicated through attribution in the referencing system described in the section on References.

  • If a quotation is in a language other than English, it is preferred if the author provides a translation of it so that readers do not miss important content.

Cross references:

  • Embedded cross references within the text are used sparingly because they can only be added at final proof stage. More general references to a chapter or section are preferred.

  • Direct page references (see p.00) are preferred rather than stating ‘on the next page’ or ‘on the previous page’. Page number references will be checked at proof stage. References are made to chapter or section headings and to table and illustration numbers as far as possible. Similarly, references to ‘the table below/above’ are not used, as what appears below/above in the draft may not appear in the same location once typeset.


  • Dates are given as in the British sequence: day month year, as in 1 January 2020.

  • Decades are expressed as the 1970s, not 1970’s or ‘70s.

  • Names of months are not contracted, except in figures, tables, or marketing materials for reasons of space.

  • The names of historical periods are usually capitalized, for example: the Middle Ages, the Jurassic, the Holocene, Iron Age, but not medieval.

  • Pairs of dates are usually reduced to their shortest pronounceable form, for example: 1914–18, 1878–79. However, an oblique is used when referring to financial years because they are made up of parts of two calendar years and should be indicated as 2003/04.


  • Fonts will be imposed during typesetting, but authors are encouraged to use Calibri size 10 in the main text and Calibri size 9 for footnotes. Heading fonts and styles will be set in the template as follows:


Footnotes and endnotes:

  • With the sole exception of bibliographic citation for web pages in footnotes, footnotes and endnotes are not used.

  • Other sources have a standard citation in the text to an entry in the References section.


  • Hyphens are used sparingly but consistently.

  • Compound adjectives are hyphenated, so ‘a nine-year-old-child’, a ‘seventeenth-century document’, but ‘the child was nine years old’, ‘the chair was made in the seventeenth century’.

  • Hyphens are not used between an adverb and part of a verb used adjectivally, for example badly drawn boy, ineptly scripted presentation.

  • Numbers from 21 to 99, and fractions, are hyphenated when written out, for example twenty-one, ninety-nine.


  • Italics are used for the names of books, exhibitions, paintings, journals and magazines, newspapers, plays, films, legal cases, epic poems, and ships (although HMS and SS in ships’ names are not italicized).

  • Many words from other languages are commonly italicized, although there is no need to italicize words that are now common in English language usage. For example, vice versa, chic, ersatz, naïve, facade and prima facie do not need to be italicized, although ipso facto, Zeitgeist, ibid., et al. and ad hoc often are.


  • Items in a list are separated by commas. When a conjunction joins the last two elements in a series of three or more, a comma (called a serial comma or Oxford comma) should appear before the conjunction to prevent ambiguity. For example:

There are several options for storage, such as optical disk, magnetic tape, and cloud storage.

  • If the last element consists of a pair joined by ‘and’, the pair should still be preceded by a serial comma and the first ‘and’. For example:

Best practice for a long-term web archiving programme avoids approaches like print to PDF, screenshots, and copy and paste.

  • A bullet point list containing substantial sentences should have a semi-colon at the end of every bullet point, an ‘and’ following the second-last item in the list, and a full stop at the end of the last item. A lower-case letter follows the bullet point. For example:

His aims were to:

        • research all the commercially available repository systems;

        • compare their functionality and costs;

        • consult the DPC Executive Guide and Business Case Toolkit; and

        • create a business case to present to his management team.

  • There is no need to punctuate if the list consists of single words or short phrases.

Numbers and measurements:

  • In the text, numbers up to ten are spelt out; after that, numerals are used. The exception is when a number starts a sentence, as then it should be written out in full.

  • If a percentage contains a decimal point, as in 5.4%, numerals are used.

  • Numbers from 21 to 99, where spelt out, and fractions, are hyphenated, such as twenty-one and two-thirds.

  • The percentage sign (%) is used in tables, illustrations, and text.

  • A ‘0’ is used in front of decimals. For example: 0.6.

  • The abbreviation ‘No.’ is used for ‘number’.

  • Numerals are used for measurements and weights, for example: 3 metres, 25 km, 4 kg. When citing measurements, use a form that conveys the precision of the measurement, for example: the ditch is 0.85m wide, the brooch is 35mm wide and 87mm long, not the ditch is 850mm wide, the brooch is 0.035m wide and 0.087m long.

  • Numbers from 1,000 onwards use commas as it makes numbers easier to read.

  • Numbers are reduced to the shortest form consistent with clarity. For example: 254–8, 343–7, but 214–18.


  • DPC Style prefers the British use of single quotation marks, or inverted commas, for speech and direct quotations.

  • For quotes within quotes, or speech within speech, double quotation marks are used.

  • In quotations, the closing quotation mark comes before a final full stop. For example: ‘In most cases, the simplest way to mitigate risks with storage media is to transfer all content into a managed storage system’.

  • The closing quotation mark comes after any punctuation mark that is not a full-stop (such as an exclamation mark) which is part of the text being quoted. For example: Before he opened his mouth, I knew he would say, ‘Digitization is not the same as digital preservation!’.

  • When the quoted speech is interrupted by a reporting verb such as ‘says’ or ‘shouts,’ and so on, the punctuation that divides the sentence is put inside the quotation marks. For example: ‘Development of services for non-technical users has come a long way,’ he argues, ‘making emulation a more viable approach’.

  • If a quoted word or phrase comes at the end of a sentence or coincides with a comma, the punctuation that belongs to the sentence as a whole is placed outside the quotation marks. For example: What is ‘bit rot’?

  • Colons and semi-colons are followed by a lowercase initial letter, except where the colon precedes a quotation or the subtitle of an exhibition or book. For example: Practical Digital Preservation: A how-to guide for organizations of any size

  • Full stops are not used at the end of headings or lists of single words.

  • Ampersands are not used in text but may be used to save space in tables.

  • The % sign is used in tables and captions but spelt out as ‘per cent’ in running text.

3. References

This section gives an overview of how DPC publications acknowledge quotations and references derived from the work of other individuals and institutions. DPC prefers the Harvard (or author-date) system of referencing. Glasgow Caledonian University Library provides a useful guide to the Harvard referencing system for further reference.[1]

In simple terms, the author, publication date (and where appropriate page number) references are given in the text and a full reference given in the list of references at the end of the publication. For example:

Experienced professionals (Brown, 2013, p.36) emphasize the importance of using real examples of digital assets at risk when presenting a business case.

If the author’s name forms part of the sentence, it is not repeated in the reference. For example:

Brown (2013) argues that ‘the benefits of ensuring their preservation, and the consequential impact arising from their loss, can then be measured in terms that will resonate most strongly with the organisation’.

If the author published more than one work in a year, publications are labelled (2014a) and so on. If more than one work by the same author is included in a reference, it appears as (2014a, b). Citations of references with three or more authors give all the authors at the first instance. For example: (Williams, Burnap, and Sloan, 2017) shortened to (Williams et al., 2017) thereafter.

When citing unpublished material, if the reader will be able to obtain the material without too much difficulty (for example, a thesis lodged at a university), a reference is included, preferably with a DOI or URL. If the material is in preparation or in press, but confirmed as accepted for publication, as much information about the source of the material is given and the entry marked as ‘forthcoming’.

All references within the text appear in the References section in Harvard format. References are listed in alphabetical order by author surname, with titles by the same author listed chronologically. Works by the author individually are listed before works co-written or works which the author has edited. Joint works are listed alphabetically by second author.

When an association, agency, or organization has produced the publication, and no author’s name appears on the title page, the name of the organization usually acts as the author for in-text references and the References section at the end of the work. Where a work has a compiling editor or editors rather than an author, the text reference is (Brown and Thomson, Eds, 2003). References to two or more works given together are separated by semicolons, for example (Brown and Thomson, 2003; Brown and Smith, 2004).

Full bibliographical references should appear as the following examples:

A book:

Harvey, R. and Weatherburn, J. (2018) Preserving Digital Materials. 3rd edn. Lanham, MD: Rowman & Littlefield.

An eBook:

Driscoll, M.J. and Pierazzo, E. (eds.) (2016) Digital Scholarly Editing: Theories and Practices. Available at: DOI: 10.11647/OBP.0095.

An eJournal article:

Williams, M.L., Burnap, P., and Sloan, L. (2017) ‘Towards an Ethical Framework for Publishing Twitter Data in Social Research: Taking into Account Users' Views, Online Context and Algorithmic Estimation’, Sociology 51(6), pp.1149-68. Available at: DOI: 10.1177/0038038517708140.

Web resources:

In line with best practice in digital preservation and scholarly citation, DPC prefers that URLs referenced in publications include a persistent link or an archived web page, wherever possible. The in-text reference to a web resource should link to the live web. In the References at the end of the work, authors should provide a persistent link, such as a Robust Link, DOI, or the most concurrent capture of a web resource in a national or international web archive, such as the Internet Archive[2] or UK Web Archive[3]. Some web archives provide their own guidance on how to cite one of their resources. Authors can find further guidance on citing archived web content from the UK Government Web Archive[4], the Bodleian Libraries’ Web Archive[5], and the National Records of Scotland Web Archive[6].

Web pages with no author:

In-text citation: FFmpeg is an important tool for preserving audiovisual materials but requires users to have a grasp of the command line interface (ffmprovisr, 2019)1.


References section:

ffmprovisr (2019) Available at (Wayback Machine capture from 23 December 2019, accessed 19 February 2020).

If a DOI or archived version of the web page does not exist, it can be referenced:

References: ffmprovisr (2019) Available at: (Accessed 19 February 2020).

Web pages that do not already exist in a web archive can be nominated to one of a number of different services, including the UK Web Archive’s ‘Save a UK Website’[7] and the Internet Archive’s ‘Save Page Now’[8].

4. Other Inclusions


These are included if they provide access to details that are too bulky or repetitive to include in the main text. Appendices are numbered consecutively, included in tables of content, and referenced numerically from within the text, for example (see Appendix A).

Further reading:

All sources provided in this section follow the style of the references but may contain short annotations or a brief description of the contents of the resource by the author.


DPC acknowledges the generous assistance of Susan Pacitti (Glasgow Museums) in preparing this document.


[1] Glasgow Caledonian University Library, Subject help, Harvard referencing: (Wayback Machine capture from 15 October 2017)

[2] Internet Archive’s Wayback Machine:

[3] UK Web Archive:

[4] UK Government Web Archive Guidance to citing archived web pages:

[5] Bodleian Libraries’ Web Archive guidance:

[6] National Records of Scotland Web Archive:

[7] UK Web Archive, Save a UK website:

[8] Internet Archive, Save Page Now:

Scroll to top