An official website of the United States government
The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before
sharing sensitive information, make sure you’re on a federal
government site.
The site is secure.
The https:// ensures that you are connecting to the
official website and that any information you provide is encrypted
and transmitted securely.
Penn ND, Corrado OJ, Pitchfork LJ, Evans RT, Mascie-Taylor BH.Penn ND, et al.Postgrad Med J. 1989 Jan;65(759):20-1. doi: 10.1136/pgmj.65.759.20.Postgrad Med J. 1989.PMID: 2780447Free PMC article.
Tindall H, Griffiths AP, Penn ND.Tindall H, et al. Among authors: penn nd.Postgrad Med J. 1987 Oct;63(744):869-71. doi: 10.1136/pgmj.63.744.869.Postgrad Med J. 1987.PMID: 3447112Free PMC article.
Griffiths AP, Penn ND, Tindall H.Griffiths AP, et al. Among authors: penn nd.Postgrad Med J. 1987 Jan;63(735):59-60. doi: 10.1136/pgmj.63.735.59.Postgrad Med J. 1987.PMID: 3671232Free PMC article.
Griffiths AP, Henderson M, Penn ND, Tindall H.Griffiths AP, et al. Among authors: penn nd.Postgrad Med J. 1988 Aug;64(754):617-20. doi: 10.1136/pgmj.64.754.617.Postgrad Med J. 1988.PMID: 3249709Free PMC article.
Travers AF, Burns E, Penn ND, Mitchell SC, Mulley GP.Travers AF, et al. Among authors: penn nd.BMJ. 1992 Apr 4;304(6831):878-9. doi: 10.1136/bmj.304.6831.878.BMJ. 1992.PMID: 1392747Free PMC article.