Syniad da!.
Davies, Helen Emanuel.
Jones, Siôn.
Edwards, Meinir Wyn.
Talybont, Ceredigion : Y Lolfa,
2009.
Teitl clawr = Cover title.
Yn cynnwys mynegai = Includes index.
Fformat pen i waered, gyda stori un ochr a gwybodaeth ffeithiol yr ochr arall = Upside down format, with story on one side and factual information on other side.
Inventors
Time travel
Inventions