APA (7th ed.) Citation

Reichert, M., Reichert, H., & Grüttner, K. (1989). Wochenpost Rätsellexikon (?).

Chicago Style (17th ed.) Citation

Reichert, Marga, Heinz Reichert, and Katharina Grüttner. Wochenpost Rätsellexikon (?). Berlin, 1989.

MLA (8th ed.) Citation

Reichert, Marga, et al. Wochenpost Rätsellexikon (?). 1989.

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