APA (7th ed.) Citation

Spyri, J., Stork, E. P., & Kirk, M. L. (2007). Heidi (Gift Edition). Project Gutenberg.

Chicago Style (17th ed.) Citation

Spyri, Johanna, Elisabeth P. Stork, and Maria Louise Kirk. Heidi (Gift Edition). Project Gutenberg, 2007.

MLA (9th ed.) Citation

Spyri, Johanna, et al. Heidi (Gift Edition). Project Gutenberg, 2007.

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