Vancouver is a 'numbered' referencing style commonly used in the sciences and medicine.
It follows rules established by the International committee of Medical Journal Editors, now maintained by the U.S. National Library of Medicine. It is also known as Uniform Requirements for Manuscripts submitted to Biomedical Journals.
When quoting or paraphrasing an author:
Emphasise the author in your citation as in the example below.
In her essay, Frankel1 asserts....
Emphasise the information in your citation as in the example below.
... as evidenced by a qualitative study.2