According to official Amazon Kindle Blog two good periodicals are not available for subscription on Kindle:
Since its founding in 1922, Foreign Affairs
has been a leading forum for serious discussion of international affairs. Experts from across the political spectrum offer timely and incisive analysis on the most crucial issues affecting foreign policy and the global economy. New subscribers to Foreign Affairs
will enjoy a 14-day free trial.
The Detroit Free Press is Michigan’s oldest and largest newspaper and known for its comprehensive news coverage of metro Detroit and Michigan. The winner of eight Pulitzer Prizes and three national Emmy Awards, the Free Press is a trusted source of information on GM, Ford and Chrysler, as well as on international auto news.
Foreign Affairs On Kindle
Detroit Free Press On Kindle