The Numbered, or Vancouver, style of referencing is commonly used in sciences and engineering. Numbered bibliographies are created according to one of two styles (see below), and the works are then cited in the text according to these numbers. The numbers are usually enclosed in parentheses or square brackets.
Style 1: Works are listed in the bibliograpy alphabetically according to the order of the first author’s last name, and are numbered consecutively; those numbers are then used persistantly for in-text citations. (The numbers will not be consecutive in the running text.)
Style 2: Works are listed in the bibliography according to the order in which they are cited in the text; those numbers are then used persistantly for in-text citations. (The numbers will be consecutive in the running text.)
In-text citations will look something like this:
Edge-finding was first applied to scheduling problems in , and since that time several efficient algorithms have been developed for the disjunctive case [10, 41].
The reference list (here made in Style 1) will look something like this:
 Abderrahmane Aggoun and Nicolas Beldiceanu. Extending CHIP in order to solve complex scheduling and placement problems. Mathematical and Computer Modelling, 17(7):57–73, 1993.
 David Applegate and William Cook. A computational study of the job-shop scheduling problem. INFORMS Journal on Computing, 3(2):149–156, 1991.
 Jacques Carlier and Eric Pinson. Adjustment of heads and tails for the jobshop problem. European Journal of Operational Research, 78(2):146–161, 1994.
 Petr Vilím, Roman Bartak, and Ondrej Cepek. Unary resource constraint with optional activities. In Principles and Practice of Constraint Programming, volume 3258 of Lecture Notes in Computer Science, pages 62–76. Springer, 2004.