Librería Samer Atenea
Kálamo Books
Librería Elías (Asturias)
Librería Kolima (Madrid)
Librería Proteo (Málaga)
A wide variety of new forms of money have been developed in recent decades as a challenge or complement to the official, dominant currencies. LETS, Local Currencies, Carbon Currencies and Bitcoins are all examples of this new trend.