Valentin Chirosca’s Reviews > Science and Civilisation in China, Volume 5: Chemistry and chemical technology, Part 2: Spagyrical discovery and invention: magisteries of gold and immortality > Status Update

What is not printed does not exist is OK for China where printing techniques exist from 220 AD. (The earliest known form of woodblock printing came from China dating to before 220 A.D. Shelagh Vainker in Anne Farrer (ed), "Caves of the Thousand Buddhas", 1990, British Museum publications, ISBN 0-7141-1447-2)