APA (7th ed.) Citation

Schwehm, G. (2006). Twenty years after Giotto: ESA's pioneering mission to comet Halley.

Chicago Style (17th ed.) Citation

Schwehm, Gerhard. Twenty Years After Giotto: ESA's Pioneering Mission to Comet Halley. 2006.

MLA (9th ed.) Citation

Schwehm, Gerhard. Twenty Years After Giotto: ESA's Pioneering Mission to Comet Halley. 2006.

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