IBM Wheelwriter/Sources

Patents
Most of these have expired by now, 20 years after invention.

IBM Hardware

 * US5000592 - Envelope addressing format feature for electronic typewriters

IBM Software

 * US4799811 - Automatic relocate on continuation of document playout
 * US4894798 - Automatic stop code insertion feature for a word processing apparatus
 * US4957380 - Tab adjust function for an electronic typewriter to permit the shifting of tabs from a first to a second format

Lexmark

 * US5038279 - Direct hot-keying with reset of printer parameters for a secondary application including a typewriter emulator

Other Manufacturers

 * US4842428 - Electronic typewriter with spell checking and correction: Brother
 * US3924722 - Typewriter with electronic keyboard: Cpt Corp

Manuals

 * Lexmark - Official Product Manuals for IBM/Lexmark Wheelwriter Typewriters

Typewriter Models

 * IBM - Typewriter History Milestones, after 1970
 * eTypewriters - IBM Typewriter History