APA (7th ed.) Citation

British Medical Association and Royal Pharmaceutical Society of Great Britain. (1990). British National Formulary (Number 20 (September 1990).). British Medical Association and Royal Pharmaceutical Society of Great Britain.

Chicago Style (17th ed.) Citation

British Medical Association and Royal Pharmaceutical Society of Great Britain. British National Formulary. Number 20 (September 1990). London: British Medical Association and Royal Pharmaceutical Society of Great Britain, 1990.

MLA (9th ed.) Citation

British Medical Association and Royal Pharmaceutical Society of Great Britain. British National Formulary. Number 20 (September 1990). British Medical Association and Royal Pharmaceutical Society of Great Britain, 1990.