Year Two: 1965

By the end of the second year of Paul et al.'s (1963) life, some inter-topic connections start to form. For example, node 2 (topic: serum cholesterol) is cited by both nodes 33 (topic: psychosocial factors) and 19 (topic: blood pressure). There are still some close connections forming within a single topic, such as nodes 3, 20, and 30, which all pertain to caffeine, but there are inter-topic connections forming at this point in time.