Apple has discontinued the iPod Nano and iPod Shuffle.
Apple adds buttons to new fourth-generation iPod shuffle
Remembering the radically ever-changing iPod nano
iPod Classic - Wikipedia
Apple Music: The Good, The Bad and the So So - Katherine Boehret - The Mossberg Solution - AllThingsD
Review: Apple iPod shuffle (Fourth-Generation)
Apple Discontinues iPod Nano and iPod Shuffle
Apple announces new iPod touch, nano, shuffle, classic; iTunes 9
Apple Shrinks the iPod Nano But Manages To Add A Touchscreen
Apple Upgrades iPod Lineup and Apple TV - The New York Times
Identify your iPod model - Apple Support
The iPod is Dead; Now Stop Being So Weepy and Start Looking at the Future - CDM Create Digital Music