I want to write an article which relies heavily on
scientific
publications. (I will of course cite the relevant articles at the end
of `my' wikipedia article). What I have in mind is a summary of their
work, maybe one of ten sentences copied literally. Do I need the
permissions of the authors of these article (one author is already
dead) or could I avoid that problem in simply not copying even a
single sentence verbatim?
Or without their explicit permission I simply could not write about
the subject?
You may quote these authors without their permission, to some extent.
From [[WP:Wikipedia:Fair use]];
"Brief, attributed quotations of copyrighted text may be used to
illustrate a point, establish context, or attribute a point of view or
idea. In general, extensive quotation of copyrighted news materials
(such as newspapers and wire services) is not fair use and is
prohibited by Wikipedia policy. Extensive quotation from copyrighted
media such as movie scripts is also prohibited, as previous "fair use"
case law has established that such usage may infringe on the future
earnings of the copyright holder (i.e. on their ability to publish a
book of said quotations)."
In general, try not to use copyrighted work under fair use unless
really necessary. You can present the same facts as a copyrighted text
using your own words without violating copyrights. It's the creative
work that is protected, not the facts. Also, remember that Wikipedia
requires attribution whenever fair use is used.