APA (7th ed.) Citation

Ruhrgas Aktiengesellschaft <Essen>. Erdgas Information Haustechnik. Ruhrgas.

Chicago Style (17th ed.) Citation

Ruhrgas Aktiengesellschaft <Essen>. Erdgas Information Haustechnik. Essen: Ruhrgas.

MLA (9th ed.) Citation

Ruhrgas Aktiengesellschaft <Essen>. Erdgas Information Haustechnik. Ruhrgas.

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