No Inv.: 127542-127546/P/Perp/10/5c
No Inv.: 128200/SM/Perp/10/1c
No Inv.: 128986/S/Perp/10/1c
No Inv.: 131960/SM/Perp/12/1c
No Inv.: 133540/S/Perp/12/1c
No Inv.: 136057,136058/SM/Perp/13/2c
Bibliografi : hlm. 207-210 No Inv.: 142093-142097/P/Perp/14/5c
No Inv.: 146986/P/Perp/15/1c
No Inv.: 10871-10880/P/Perp/98/10c
Judul asli : "The Skill of Communicating"