Most of the solder the electronic industry uses today is of the lead-free variety, as use of lead has been recognized as a health hazard.
Soldering - Radio/TV transmitter superstore
How to deal with air bubbles in solder joints during PCBA process? - IBE Electronics
Soldering - Wikipedia
Solder Joint - an overview
Dry Solder Joints: How to Identify and Fix Them? - NextPCB
Why Solder Joint Inspection Is Important
How to tell if a solder joint is good Terry Love Plumbing Advice & Remodel DIY & Professional Forum
Micromachines, Free Full-Text
Making a good solder joint, Adafruit Guide To Excellent Soldering
Industrial Soldering Training
Cold Solder Joint - The Definitive Guide To Soldering
Seymour Duncan How to Solder: An Introduction to Soldering for Guitarists
Top 5 Reasons for Solder Joint Failure
How to deal with air bubbles in solder joints during PCBA processing?