Complex sentence: As any drum corps member's career is based upon countless public performances over the years, which may or may not have been recorded by various companies, there is yet no complete discography of all recordings of Markovich's performances.
Split into simpler sentences: As any drum corps member's career is based upon countless public performances over the years, which may or may not have been recorded by various companies. There is not yet a complete discography of all recordings of Markovich's performances.