In the Vancouver system, the only indication required in the text of a paper is a number, allocated in ascending sequence, and presented in the text either in brackets, some or in superscript. For example:
"Recent randomized controlled trials in primary care showed benefits for patients with depression from increased telephone support, better cooperation between primary care and mental health professionals, and more systematic follow up.7"
If the same source is cited again later in the text, the same number is used once more. If multiple references are cited, use a hyphen to join an inclusive range of numbers thus: 2-5. Use commas without spaces to separate non-inclusive numbers in a multiple citation thus: 2-5,7,10.