Genotype-Environment Correlation (rGE)
Here's your citation in American Psychological Association (APA) format:
Genotype-Environment Correlation (rGE). (n.d.). In Alleydog.com's online glossary. Retrieved from: https://www.alleydog.com/glossary/definition-cit.php?term=Genotype-Environment+Correlation+%28rGE%29