- Livre électroniqueSouthwest Treasure Hunter's Gem and Mineral Guide (6th Edition)Kathy J. Rygle
- Livre électroniqueSoutheast Treasure Hunter's Gem & Mineral Guide (6th Edition)Kathy J. Rygle
- Livre électroniqueNortheast Treasure Hunter's Gem & Mineral Guide (5th Edition)Kathy J. Rygle
- Livre électroniqueNorthwest Treasure Hunter's Gem and Mineral Guide (6th Edition)Kathy J. Rygle
- Livre électroniqueNorthwest Treasure Hunter's Gem and Mineral Guide (5th Edition)Kathy J. Rygle
- Livre électroniqueNortheast Treasure Hunter's Gem and Mineral Guide (6th Edition)Kathy J. Rygle