Is it allowed to link to material that it's copyright period has expired ?
I found a scanned book that was published in 1974 that covers ttl devices, so am just curious.
Even though the book was published 39 years ago, the copyright may not have expired. Over the years, to appease their obscenely rich masters, the U.S. government has essentially extended the copyright on some material to "indefinite".
What book (title and author)?
What evidence can you provide that the copyright has expired?
I assumed that, in my country where we do not yet have indefinite copyright, that any material not re-assigned copyright after its 25 year licensing had expired.
For most countries there is a fair use policy.
If you link to one page or one article for a specific use/explanation, that is often not a problem.