Perygl perffaith /
Paulsen, Gary,1939-
Roberts, Esyllt Nest.
Llanrwst : Gwasg Carreg Gwalch,
2003.
Addasiad Cymraeg gan = Welsh adaptation by : Esyllt Nest Roberts.
Argraffiad Saesneg gwreiddiol = Original English edition : New York : Bantam Doubleday Dell, 1996.
Laboratories