Heybroek, H. M.; Elgersma, D. M.; Scheffer, R. J. (1982). „Dutch elm disease: An ecological accident”. Outlook on Agriculture. 11 (1): 1—9. S2CID127174310. doi:10.1177/003072708201100101.
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Heybroek, H. M.; Elgersma, D. M.; Scheffer, R. J. (1982). „Dutch elm disease: An ecological accident”. Outlook on Agriculture. 11 (1): 1—9. S2CID127174310. doi:10.1177/003072708201100101.