Type II: Closed Natural System Models

Most of these are from the human relations group, and remained focused on internal organizational actions.

Social Psychological

In the human relations group, Whyte (1959) and Roy (1952) looked at informal group processes.

Structural Level

Barnard's cooperative systems (1938) focused on internal processes, though he didn't completely neglect the environment.

Mayo (1945) and Dalton (1959) of the human relations group also focused on internal elements.