Project Gutenberg encourages the use of multiple printed sources to
create an eBook. For many historical works, including the US
Declaration of Independence (the first Project Gutenberg eBook), there
are variations among the printed sources. Another early example is the
works of William Shakespeare. Project Gutenberg has several different
versions of Shakespeare, including one based on the first edition
folios. It has been typical, throughout the modern history of
publishing, for different versions of a book to have variations.
In practice, the majority of Project Gutenberg eBooks rely on a single
printed source. However, even those items might benefit from other
sources — such as when some pages are missing, or illustrations come
from a different version, or when typos/errata reports come from other
sources.
It is a principal of Project Gutenberg that the eBooks in the collection
are denoted as Project Gutenberg eBooks. Even if the publisher imprint
and frontispiece from a printed work is included, there is no assurance
that the content exactly matches that printed work. And, in fact,
it will not match: minimally, the headers/footers will be removed, and
paragraphs will flow together such that they span the pages of the
printed source. Many other adjustments are typically made, as mentioned
above.
For this reason, Project Gutenberg’s online catalog metadata does not
include a citation to the source(s) used to create an eBook. Instead,
Project Gutenberg should be cited as the publisher. For example, a
bibliographic citation might have a form such as this:
Carroll, Lewis. “Alice’s Adventures in Wonderland.” Urbana, Illinois:
Project Gutenberg. Available: www.gutenberg.org/ebooks/11