Computer Security: Businesses at Risk By R.R.C. Penfold

Easy PC Upgrading, Penfold, R. A.

Boost Your PC's Performance By R. A. Penfold

Circuit Source: Bk. 2 (BP S.) - Penfold, R. A. 1990s Paperback *C

Practical Midi Handbook by R. A. Penfold Paperback Book The Fast Free Shipping

A Beginner’s Guide to TTL Digital ICs. R.A. Penfold. 1993. Logic Circuits Book

Getting the Most from Your Multimeter (BP), R.A. Penfold, Used(Paperback, 1988)

How to Build a Computer Made Easy-R. A. Penfold