Citation Guide: Number reference system

The alphabet number reference system is a variation of the number reference system.
Bibliographic references are arranged in alphabetical order (not in consecutive order).
The format of the in-text citation is similar to the number reference system.

The alphabet number reference system is commonly used within the technical sciences, also in some departments of Aalto University.

In the number reference system, a number is added in parentheses or square brackets in the appropriate place in the text, starting the numbering from 1. The bibliography of the work is arranged by the order in which the citations appear in the text.

This system is not as easy for readers to follow as the Harvard referencing system, but from a writer's point of view the system is practical in that it does not affect the structure of the text. Using the numeric system is particularly justifiable if the resources include directories or other similar materials that do not have an author. Maintaining the number reference system without the help of reference management software is more difficult than the Harvard referencing system.

The referencing style of IEEE is different from other number reference systems in the order of authors' names, as the references begin with authors' given names. This style is used especially in the field of electrical engineering. IEEE Reference Guide is available here: https://ieeeauthorcenter.ieee.org/wp-content/uploads/IEEE-Reference-Guide.pdf

In the number reference system the references are listed in numerical order as they appear in the text.

Examples:

• Recent research showed that... [1].
• Further research has proved that... [2, p. 36-38].
• According to the theory presented by Järvinen in 2000... [3, p. 50]. Author's name and publication year can be noted in in-text citation. 

[1] Amjad, Z. Advances in crystal growth inhibition. New York, New York, USA: Kluwer Academic Publishers, 2000. 277 p. ISBN 0-3064-6924-3 (electronic). ISBN 0-3064-6499-3 (printed).

[1] Laakkonen, Pertti. Otahalli got a new flooring. Colour and surface, 2004. Vol. 87:4. P. 49-50. ISSN 0024-8568.

[1] Lassalle, V. L. & Failla, M. D. & Vallés, E. M. & Martin-Martinez, J. M. Chemical modification of styrene-butadiene-styrene co-polymer by grafting of N-carbamyl maleamic acid. Journal of adhesion science and technology. 2005, vol. 18:15. P. 1849-1860. Available at: doi:10.1163/1568561042708359.