Spellman, F. R. (2015). Economics for environmental professionals. Taylor and Francis.
Chicago Style aipamenaSpellman, Frank R. Economics for Environmental Professionals. Boca Raton: Taylor and Francis, 2015.
MLA aipamenaSpellman, Frank R. Economics for Environmental Professionals. Taylor and Francis, 2015.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.