Each issue is published in print and an electronic edition.
The electronic edition was available without charge, as an open access journal, but since 2008 this is no longer the case.
Some of the new electronic editions have brought that idea closer to reality.
However, no sales figures are currently available for these electronic editions.
An electronic edition will round out the project at an unspecified future date.
A few sponsor database services; almost none shows interest in electronic editions.
But for now, such instant updates are not the main purpose of many electronic editions.
(the electronic 3rd edition is freely available on author's site).
Barnesandnoble.com said it would charge $5.95 to $7.95 for its electronic editions, and always less than a printed equivalent.
There is also a free electronic edition with a different title: .