Affect control theory
Biochemical systems theory
Biocybernetics
Biological systems engineering
Chaos theory
Complex adaptive system
Complex systems
Complexity economics
complexity theory and organitations
Complexity theory and strategy
Computaional systems biology
Control engineering
Control system
Control theory
Cybernetics
Developmental sytems theory
Dynamical systems theory
Earth systems engineering and management

Ecological systems theory

Ecosystem ecology
Engineering cybernetics
Enterprise systems engineering
Living systems theory
LTI system theory
Management cybernetics
New cybernetics
Second-order cybernetics
Social dynamics
Sociotechnical systems
Synthetic biology
System dynamics
Systemic therapy
Systems analysis
Systems ecology
Systems immunology
Systems psychology
Systems science
Systems theory