Παραπομπή APA

Sehgal, R. (1994). Introduction to universal decimal classification. Ess Ess.

Παραπομπή Chicago Style

Sehgal, R.L. Introduction to Universal Decimal Classification. New Delhi: Ess Ess, 1994.

Παραπομπή MLA

Sehgal, R.L. Introduction to Universal Decimal Classification. Ess Ess, 1994.