In the case of a joint work in which each contribution consists of an integral part of the work as a whole, all the contributors shall be considered coauthors and co-owners of copyright in the work. However, if it is possible to distinguish the contribution of each author from the others, each of the joint authors shall be considered the author of his own contribution.
The term of protection granted shall be the life of the author and 50 years after his death, to be computed from the end of the year in which the death has occurred.
NO, but highly recommended to be effective against third parties.
YES, imprisonment and fine.