APA (7th ed.) Citation

Pierre, d. M. The Letter of Petrus Peregrinus on the Magnet, A.D. 1269.

Chicago Style (17th ed.) Citation

Pierre, de Maricourt. The Letter of Petrus Peregrinus on the Magnet, A.D. 1269.

MLA (9th ed.) Citation

Pierre, de Maricourt. The Letter of Petrus Peregrinus on the Magnet, A.D. 1269.

Warning: These citations may not always be 100% accurate.