No Inv.: 83318-83319/P/Perp/02/2c
No Inv.: 3932/P/Perp/91/1c~1026/P/Perp/94/1c
Judul asli : "Earth Our Crowded Space Ship"
No Inv.: 11699-11708/P/Perp/93/10c~1641-1660/P/Perp/97/20c
No Inv.: 9447-9451/P/Perp/97/5c
No Inv.: 1779-1780/Pb/Perp/92/2c~8966-8969/P/Perp/92/4c~4431-4440/P/Perp/97/10c
Bibliografi : hlm. 172-174
No Inv.: 116569/P/Perp/09/1c
No Inv.: 108603-108607/P/Perp/06/5c~142646-142650/P/Perp/14/5c