1. The resistance of the Bain and Penlon co-axial circuits
2. A streamlined anaesthetic system
3. The Lack anaesthetic system An assessment during spontaneous ventilation
4. J. A. Dorsch, and S. E. Dorsch (1984 ) Understanding Anesthesia Equipment . 2nd edn , Williams and Wilkins, Baltimore, p182 .
5. L. W. Hall, and K. W. Clarke (1983 ) Veterinary Anaesthesia . 8th edn , Bailliere Tindall, London, p172 .