Below is an instruction that describes a task, paired with an input that provides further context. Write a response that appropriately completes the request.

### Instruction:
List at least three different sources to prove a certain fact.

### Input:
Alzheimer's disease is the most common form of dementia.

### Response:
To prove that Alzheimer's disease is the most common form of dementia, sources may include the World Health Organization, the Centers for Disease Control and Prevention, and the Alzheimer's Association.