It's a fine line between copyright infringement and quoting or using some bars as a parody.

It's interesting to note that using other people's work in your music was not seen as bad as it is now. In the early days of music, it wasn't seen as plagiarism, and the composer did it all the time. Maybe as a tribute or as a learning mechanism (learn from the greats). Nothing is completely original if you think about it, there's always something from others in your work. And that's fine.

Thanks for sharing!