Renault 4 Manuals and Handbooks
A new manual from Haynes was £25 plus postage plus VAT last time I looked, so it's worth seeing if there are any on eBay. Make sure the manual covers your car. The most common manuals are pre-1979 and these don't cover the GTL.
The factory manuals are a must have for any enthusiast. I built my chassis jig using information from a 1972 factory manual - the Renault 4 body and chassis didn't change much from then.