APA (7th ed.) Citation

Rijswick, H. v., Jay, F. W., & Frank Webster Jay Collection. Autograph letter signed: [Xanten, Germany], to unknown person, n.p.

Chicago Style (17th ed.) Citation

Rijswick, Henrick van, Frank Webster Jay, and Frank Webster Jay Collection. Autograph Letter Signed: [Xanten, Germany], to Unknown Person, N.p.

MLA (8th ed.) Citation

Rijswick, Henrick van, et al. Autograph Letter Signed: [Xanten, Germany], to Unknown Person, N.p.