1.   One technique was to change handwriting styles.

2.   The age range determined for each document matched previous estimates from a technique called paleography, which is based on changes in handwriting styles over time.

3.   Their evidence was mostly physical, but more fascinating to Gates than the implications of paper, ink, and handwriting style was the internal evidence.

4.   The bureau described in detail the envelope, handwriting style and other characteristics found on the attack letters.