Monozygotic+Twins+%28Identical+Twins%29
Here's your citation in American Psychological Association (APA) format:
Monozygotic+Twins+%28Identical+Twins%29. (n.d.). In Alleydog.com's online glossary. Retrieved from: https://www.alleydog.com/glossary/definition-cit.php?term=Monozygotic%2BTwins%2B%2528Identical%2BTwins%2529