Classic texts: Pereira 1854.
Classic texts: King's 1898.
Henriette's herbal blog: The PD stands for product development, in case you were wondering.
Henriette's herbal blog: The making of peppermint sugar.
Henriette's herbal is one of the oldest and largest herbal medicine sites on the net. It's been online since 1995, and is run by Henriette Kress, a herbalist in Helsinki, Finland.
Plant Healer Magazine: Very relevant to the practitioner.
http://www.henriettes-herb.com - Copyright 1995–2015 Henriette Kress.