APA
P S Das, . (1987). An introduction to Manual Telephony : for the undergraduate students of Tele-Communication and Electrical Engineering. Modern Book Agency, Calcutta: .
Chicago
P S Das, . 1987. An introduction to Manual Telephony : for the undergraduate students of Tele-Communication and Electrical Engineering. Modern Book Agency, Calcutta: .
Harvard
P S Das, . (1987). An introduction to Manual Telephony : for the undergraduate students of Tele-Communication and Electrical Engineering. Modern Book Agency, Calcutta: .
MLA
P S Das, . An introduction to Manual Telephony : for the undergraduate students of Tele-Communication and Electrical Engineering. Modern Book Agency, Calcutta: . 1987.