JBL Under Armour Wireless In-Ear Headphones with Heart-Rate Monitor - – 6ave Electronics
JBL Under Armour Sport Wireless Heart Rate In-Ear Headphones Review » Technically Well
Paper: Accurate detection of heart rate - cosinuss°
UA Sport Wireless Heartrate Headphones review: Under Armour's new sports headphones track your heart rate (hands-on) - CNET
JBL Under Armour Wireless In-Ear Headphones with Heart-Rate Monitor - – 6ave Electronics
Running headphones with heart rate monitor
Amazon.com: Jabra Elite Sport Earbuds – Waterproof Fitness & Running Earbuds with Heart Rate and Activity Tracker, True Wireless Bluetooth Earbuds with Superior Sound, Advanced Connectivity and Charging Case : Electronics
Biohacking : Ear Based Heart Rate Monitoring « Adafruit Industries – Makers, hackers, artists, designers and engineers!