Encyclopedias/Atlas and Tin-tin books (in English)

Very good condition:
Penguin reference encyclopedia
Encyclopedia of Science
National Geographic Collegiate Atlas
(all three for 10 euros)

OR

Three Tin Tin Books (one hardbound and one soft bound both in good condition and one soft bound  in fair condition):
Calculus Affair
The secret of the Unicorn
Explorers on the moon
(all three for 10 euros)