Pickard, R. (1996). Conservation in the built environment. Longman.
Chicago Style aipamenaPickard, Robert. Conservation in the Built Environment. Harlow, Essex: Longman, 1996.
MLA aipamenaPickard, Robert. Conservation in the Built Environment. Longman, 1996.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.