German book publisher that started releasing sacred music on records in the early 1960s. It's the short version of either Pädagogischer Verlag Schwann GmbH or L. Schwann Verlag.
The credit appears, from the mid-70s on, as [Publisher] "Schwann Düsseldorf" or "℗ Schwann Düsseldorf" and "© Schwann Düsseldorf" on the company's record releases, later often just shortened to ℗ Schwann" and "© Schwann" etc. Please use Schwann in these cases only with the corresponding company roles.
The company used "Schwann" shortly as a label in the mid-70s for a series of children's books (with attached 7" records released on Schwann Single) - see label.