Similar stories by other writers followed through 1929 and 1930; by 1931 the space opera was well-established as a dominant sub-genre of science fiction.
By 1931, the space opera was well-established as a major sub-genre of science fiction. Similar stories by other writers followed through 1929 and 1930.
Similar stories by other writers followed through 1929 and 1930. By 1931, the space opera was well-established as a major sub-genre of science fiction.
Similar stories by other writers followed through 1929 and 1930. By 1931, the space opera was well-established as a major sub-genre of science fiction.