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

Easy PC Upgrading (BP) By R. A. Penfold

Easy PC Upgrading (BP)-R. A. Penfold

Power Supply Projects, R. A. Penfold Bernard Babani BP76

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

Practical Electronic Building Blocks Book 2 by R.A. Penfold Paperback - RARE

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

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