Cita APA (7th ed.)

Bekkering, B., & Bekkering, G. (1988). Piece by Piece: A History of the Jig-saw Puzzle in the Netherlands. Van Soeren und Co..

Cita Chicago (17th ed.)

Bekkering, Betsy, i Geert Bekkering. Piece by Piece: A History of the Jig-saw Puzzle in the Netherlands. Amsterdam: Van Soeren und Co., 1988.

Cita MLA (8th ed.)

Bekkering, Betsy, i Geert Bekkering. Piece by Piece: A History of the Jig-saw Puzzle in the Netherlands. Van Soeren und Co., 1988.