Cita APA (7th ed.)

Checkland, P., & Scholes, J. (1999). Soft systems methodology: A 30 year retrospective. John Wiley and Sons.

Cita Chicago (17th ed.)

Checkland, Peter, i Jim Scholes. Soft Systems Methodology: A 30 Year Retrospective. Chichester: John Wiley and Sons, 1999.

Cita MLA (9th ed.)

Checkland, Peter, i Jim Scholes. Soft Systems Methodology: A 30 Year Retrospective. John Wiley and Sons, 1999.