Update external link to techwiki
http://scratchpad. wikia.com/wiki/ZX_Spectrum_technical_information The Tech Wiki] which contains corrections to some of the material in the c.s.s faq reference section, and details of new projects such as the ULAplus, and the "128Ke" idealised Spectrum 128K specification.
[http://www.sinclairfaq.org/cssfaq/index.html The comp.sys.sinclair FAQ] which contains the majority of the technical information about the Sinclair ZX80, ZX81, and Spectrum range of computers
[http://www.worldofspectrum.org/WoSFAQ.html The WoS FAQ]