The answer will depend on (a) where the works were first published and (b) exactly when. Here's a website that has a chart with all the relevant rules. I assume these works were published abroad, so use that section of the chart, and then check dates for each specific work.
http://www.copyright.cornell.edu/resources/publicdomain.cfm
Good luck.
Law Professor
Professor of Law at Top-Tier Law School, specializing in patent & copyright