Messengers of God: A Jewish Prophets Who's Who - Ronald H. Isaacs - Google Books

http://books.google.de/books?id=IEroHPQrlOAC&pg=PA231&dq=ma+tovu+Isaacs&hl=de&sa=X&ei=qIghU-XXGK-f7gaFp4HwBA&ved=0CDQQ6AEwAA#v=o

There were fifteen important prophets in Israel, whose lives covered nearly four centuries, beginning about 750 B.C.E. Known as the literary prophets because they wrote down their prophecies, they were chosen by God at a time of social and political crisis…