Please answer the following question: Given the following passage  "The modern era of comics in Japan began after World War II, propelled by the success of the serialized comics of the prolific Osamu Tezuka and the comic strip Sazae-san. Genres and audiences diversified over the following decades. Stories are usually first serialized in magazines which are often hundreds of pages thick and may over a dozen stories; they are later compiled in tankōbon-format books. At the turn of the 20th and 21st centuries, nearly a quarter of all printed material in Japan was comics. translations became extremely popular in foreign markets—in some cases equaling or surpassing the sales of domestic comics.",  answer the following question. Note that the answer is present within the text.  Question: What is done before comic stories are put into tankoban-format books?
Answer:
serialized in magazines