Will be on offer for 7 day's on Amazon in honor of
Max Planck's 157th Birthday
on 23rd April, 2015.
Offered on Kindle Countdown Deals at only:
Only $0.99 (USD)
Friday 17th April - Thursday 23 April, 2015 (PST)
Original list price: is $5.49
This is a Kindle Countdown Promotion only available to customers via: