Lingard, L. (2015). Avoiding prepositional pile-up. Perspect Med Educ.
Chicago Style aipamenaLingard, Lorelei. "Avoiding Prepositional Pile-up." Perspect Med Educ 2015.
MLA aipamenaLingard, Lorelei. "Avoiding Prepositional Pile-up." Perspect Med Educ 2015.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.