The idea originated with the School of Salamanca in the 16th century, and was developed in its modern form by Gustav Cassel in 1916, in The Present Situation of the Foreign Trade.
Η ιδέα προήλθε με τη Σχολή της Σαλαμάνκα του 16ου αιώνα και αναπτύχθηκε στη σύγχρονη μορφή της, του Gustav Cassel σε 1918.