CK-12 Foundation
Ck 12: Physical Science: Hydrocarbons
[Free Registration/Login may be required to access all resource tools.] Discusses the two different classes of hydrocarbons and their properties, uses and sources.
Georgia State University
Georgia State University: Hyper Physics: Aromatic Hydrocarbons
A definition for an aromatic hydrocarbon is given, along with examples, that show the structure of common aromatic hydrocarbons.