The standard stream corresponding to Income No. 3 is constant in real terms... We ask... how much he would be receiving if he were getting a standard stream of the same present value as his actual expected receipts. This amount is his income.

p. 184 as cited in: Asheim, Geir B. "Economic analysis of sustainability." Justifying, Characterizing and Indicating Sustainability (2007): 1-15. - Value and capital, (1939)