.Blank, L. T., & Tarquin, A. (1983). Engineering economy (6th. ed.). McGraw-Hill.

.Blank, Leland T., and Anthony Tarquin. Engineering Economy. 6th. ed. Boston: McGraw-Hill, 1983.

.Blank, Leland T., and Anthony Tarquin. Engineering Economy. 6th. ed. McGraw-Hill, 1983.