BuzzFeed Article: 5 Reasons Why Vincent van Gogh was Jack the Ripper
Provides a quick look at some of the evidence, including a handwriting comparison. Synopsis for Vincent Alias Jack
I have provided a short summary of the book here and also a paper on the details of how Van Gogh killed his father.
The best place to find info on the Jack the Ripper murders: victim photos, articles, Ripper letters, and much more. Also, follow the discussion about VINCENT ALIAS JACK on the forum at:

Jack the Ripper Site
For everything mysterious, this is a fun site filled with lots of curiosities. Join the discussion about VINCENT ALIAS JACK on their forum at:

Van Gogh Ripper on
True Crime Uncensored
The legendary Burl Barer interviews True Crime writers.
Fascinating interview of Dale Larner about VINCENT ALIAS JACK.

Van Gogh Ripper Interview

The Times
Newspaper archive for London news of the past.

National Archives of the UK
Look up police records and Ripper letters.

The National ArchivesThe Van Gogh Museum

Van Gogh MuseumThe Van Gogh Letters at the Van Gogh Museum
Comprehensive and complete.

The Van Gogh Letters at WebExhibits
Another English translation of the letters.

The Van Gogh Gallery
Lots of Van Gogh info, paintings and drawings.

The London Typographical Society
Old maps of London.