Introduction
This page a concise translation of Einführung and offers an introduction to the subject of citations. It covers key aspects such as background information, considerations for selecting suitable sources, the different types of citation and how to incorporate them into academic texts.
The reference numbers used in these examples to indicate the source are provided for illustrative purposes only. They comply with the IEEE citation style. For guidance on the formal presentation of citations and reference lists, please refer to the chapter on citation methods and styles.
Why quote?
Evidence of one's own academic work
Distinguishing between one’s own ideas and those of others
Ensuring that the work of others can be traced
Verifying others’ ideas
What are citable sources?
Primary/secondary literature (as a rule, use primary literature)
Grey literature (check with your supervisor before using this)
Wikipedia (the use of Wikipedia is assessed differently, so check with your supervisor)
Encyclopaedias: no anonymous articles; use specialist encyclopaedias only
Types of quotations
As well as direct quotations, where the words are quoted word for word, there are also indirect quotations, where the words are paraphrased. The meaning of what is quoted must be preserved in both types of quotation.
Direct quotation
Characteristics:
In a direct quotation, the source's wording is reproduced word for word.
Direct quotations are set apart from the main text by quotation marks.
Example:
“The Leaning Tower of Pisa is an Italian Romanesque building.” [1, p. 13]
The wording of the quotation must not be altered in any way. Nothing may be omitted or added. Printing errors and spelling mistakes will not be corrected. Old spellings are not converted to new spellings. Any errors or old spellings are marked after the misspelt word with the Latin [sic!], meaning 'exactly as written'.
Example of a direct quotation containing a spelling mistake:
“The croked [sic!] Tower of Pisa.” [1, p. 13]
Omissions are permitted, provided that the meaning of the quotation is not altered. The following example illustrates this, showing how a subordinate clause that is irrelevant to the meaning of the quotation can be omitted. Omissions of a single word are indicated by [.], and omissions of more than one word are indicated by [...].
Example of a direct quotation with an omission:
“Quote quote quote [...] quote quote quote.” [2, p. 17]
Indirect quotation
Characteristics:
In an indirect quotation, the original text is paraphrased.
It must be clear where the quotation begins and ends:
The end is easy to identify due to the formal marking. The beginning of an indirect quotation can be distinguished from one’s own thoughts either formally or linguistically.
Example of a formal solution:
Academic writing skills can only be developed during a degree programme within a specific academic discipline [3, p. 5, 4, p. 7]. The types of text produced during a degree programme should therefore strengthen students' academic writing skills [4, p. 7]. Furthermore, these types of text prepare students for the writing they will do in their future careers [5, p. 8]. The term 'academic writing' is therefore proposed for these forms of writing, as it encompasses both academic and professional writing [5, p. 8].
Example of a linguistic solution:
As demonstrated by Pohl [3, p. 5] and Steinhoff [4, p. 7], the development of academic writing skills is linked to a particular academic discipline and takes place during a degree programme. The types of text produced during a degree programme should therefore help students to strengthen these skills. According to Girgensohn and Sennwald [5, p. 8], these types of text also prepare students for professional writing. They therefore propose the term academic writing to describe these forms of writing.
Note:
The linguistic solution shows a stylistic approach called the 'author's voice' that names the author in the sentence. This is not common in all disciplines and rather sparingly in the natural and engineering sciences (Kruse, 2007, p. 75).
Integrating quotations into the text
Further examples of how to incorporate quotations into the text (see also The University of Manchester, 2019):
According to Müller, ...
A study by the Fraunhofer Institute shows that ...
In accordance with DIN 5008...
In addition, students should clarify whether critical commentary is required when writing texts. Whilst the author in the first example below shares Müller’s opinion – that is, presents it neutrally – in the second example 2 he states that he disagrees with Müller. This must, of course, be justified.
Example of a neutral account:
Müller emphasises...
Example of a judgemental account:
Müller claims...
bibTutorial | Last updated 06/2026
Offered by Hochschulbibliothek der Technischen Hochschule Mittelhessen (Impressum)
Some of the content on this page is in German also published on the page "Wissenschaftliche Texte schreiben - Leitfaden zur Erstellung wissenschaftlicher Texte für Studierende des Fachbereichs Wirtschaftsingenieurwesen der THM" (Shadabi, Thiel und Waigant, 2020).