[Haskell] A Gentle Introduction to Haskell Version 98

Hello, the web page under http://haskell.org/tutorial/ says: This is the master HTML version of the Gentle Introduction To Haskell, version 98. Revised June, 2000 by Reuben Thomas. However, the Postscript, gezipped PDF, PDF and DVI versions don't mention Reuben Thomas as co-author and have October 1999 as their date. The downloadable HTML version doesn't mention Reuben Thomas too and has September 28, 1999 as its date. So what is true? Ist the online version different from the download versions and is the downloadable HTML version different from the other download versions? Did Reuben Thomas modify the tutorial? Which versions do contain his modifications, which not? Best wishes, Wolfgang