I've spent much time searching about the situation I'm in, before I post this question.
I have a poetry page (working for it currently) and I want users to be able to download poem in PDF, DOC, and TXT, But I don't want to have duplicate content issue, in any means, but also don't want to use no-follow for these files because I want search engines also now about it, because if someone searches for filetype:ext
to find my pages.
I know I can set link canonical in head tag in .html
version but how to do it for files?
To be clear poems are structured like this:
/poets/name-surname/poems/123.poem-title.htm
this is main, next 3 versions are linked from this page, not from anywhere else./poets/name-surname/poems/123.poem-title.pdf
this is the PDF version./poets/name-surname/poems/123.poem-title.doc
is MS doc./poets/name-surname/poems/123.poem-title.txt
is plain text.