The copyright on "The Entertainer" was registered December 29, 1902, along with two other Joplin rags, "A Breeze from Alabama" and "Elite Syncopations", all three of which were published by John Stark & Son of St. Louis, Missouri [REF].
"The Entertainer" also appeared in orchestration as part of The Red Back Book of Standard High Class Rags, popular with ragtime bands.