56. In the apparatus of claim 54 and wherein: the first receiving means and the extraction means are included in a first document processing system; the third receiving means and the composition means are included in a second document processing system; and the second receiving means includes network means connecting the first document processing system and the second document processing system.
56. In the apparatus of claim 54 and wherein: the first receiving means and the extraction means are included in a first document processing system; the third receiving means and the composition means are included in a second document processing system; and the second receiving means includes network means connecting the first document processing system and the second document processing system. 57. In the apparatus of claim 56 and wherein: the second receiving means begins providing the interchange structure to the network means before the extraction means has finished producing the interchange structure; and the composition means begins producing the second structure before it has received all of the interchange structure from the network means.