Tolong jelaskan mengenai Lihat pula dari Spesies cincin

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Moritz, C., C. J. Schneider, et al. (1992) "Evolutionary relationships within the Ensatina eschscholtzii complex confirm the ring species interpretation." Systematic Biology 41: 273-291.

Nova Scotia Museum of Natural History: Birds of Nova Scotia

Adriaens, P. "Hybrid Gulls Breeding in Belgium"