PONTIFICIAE ACADEMIAE SCIENTIARVM SCRIPTA VARIA - 28 
CONTENTS 
FOREWORD. 
MODELLING ECONOMIC SYSTEMS. 1. The background. - 2. Models and 
their environment. 
MODELS, POLICIES AND PLANS. I. Models: a) Variables, b) Relationships. 
c) Estimation, d) Computability. - 2. Policies. - 3. Plans. 
II. A DUAL MODEL OF ECONOMIC GROWTH. I. A new development. - 2. Steady 
states and transient states. - 3. Why a dual model? 
THE STEADY-STATE MODEL, 1. Introduction. - 2. The variables. - 3. The 
relationships: a) The circuit of real flows, b) The price circuit, ¢) The 
foreign trade circuit, d) The circuit od education and training, e) The 
financial circuit, f) The circuit of research and development. - 4. The 
methods of estimation: a) Exogenous final demand, b) Endogenous 
final demand, ¢) Intermediate demand, d) Output levels, e) The in- 
dustrial distribution of labour, f) Changes in the spectrum of skills. - 
5. The computing sequence. 
«THE TRANSIENT MODEL. 1. Introduction. - 2. The relationships. 
VI. CONCLUSIONS. 
À LIST OF WORKS CITED. 
DIAGRAMS 
1, À model in its environment. - 2. A corrective device for economic 
models. - 3. A dual model of economic growth. - 4. The steady-state model 
TABLES 
1. A provisional social accounting matrix for Britain, 1962. - 2. The 
computing sequence. 
Stone - pag. 86