Oral sources or personal communication refers to e.g. interviews, lectures, phone conversations, letters or emails. If you are citing an oral source, always make sure you have the permission from the person in question to cite the source.
In practice citing oral sources varies. In the reference list all information necessary for the study should be included, e.g., the person’s name and position, a description of the communication situation and time. It’s recommended that oral sources are listed separately from other sources.
According to some recommendations oral sources should not be included at all in the reference list, as personal communication can’t be accessed by the reader. Instead, citations to oral sources could be placed in a footnote at the page where it is cited.
If your research material consists of interviews, the sources can be anonymized, but should still be cited in a way that the reader can distinguish them from one another. Note that interviews that are part of your empirical material are not oral sources. they can e.g. be presented in an appendix.
Person, position, type of material, date.
Johnson, John, XYZ Ltd, Sales Manager, Helsinki, interview 23 November 2020.
Eriksson, Stefan, Staff Ab, Staff Manager, email 7 September 2020.
Langbroek, Dick, Personnel planning in the National Library of the Netherlands. Talk at the conference Innovation through collaboration, Toulouse 2 September 2009.
At XYZ Ltd. several measures to improve sales has been… (J. Johnson, interview 21 September 2020).
It is apparent that … (S. Eriksson, e-mail 13 January 2020).
It was clear that the company… (S. Eriksson, e-mail 13 January 2020).
Langbroek (talk 2.7.2020) points out that…