Harkirat, S. (1980). Productivity News. NPC.
Chicago Style aipamenaHarkirat, Singh. Productivity News. New delhi: NPC, 1980.
MLA aipamenaHarkirat, Singh. Productivity News. NPC, 1980.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.
Harkirat, S. (1980). Productivity News. NPC.
Chicago Style aipamenaHarkirat, Singh. Productivity News. New delhi: NPC, 1980.
MLA aipamenaHarkirat, Singh. Productivity News. NPC, 1980.