APA (7th ed.) Citation

Musschenbroek, P. v., Jay, F. W., & Frank Webster Jay Collection. (1761). Autograph letter signed: N.p., to unknown person, n.p.

Chicago Style (17th ed.) Citation

Musschenbroek, Petrus van, Frank Webster Jay, and Frank Webster Jay Collection. Autograph Letter Signed: N.p., to Unknown Person, N.p. 1761.

MLA (8th ed.) Citation

Musschenbroek, Petrus van, et al. Autograph Letter Signed: N.p., to Unknown Person, N.p. 1761.