found: Howes dict. of useful and everyday plants(common hawthorn=Crataegus monogyna; syn: C. oxycantha, may, quick or whitethorn)
found: Web. 3(English hawthorn; syn: C. oxyacantha, C. monogyna)
found: Hortus 3(monogyna; syn: English hawthorn)
found: SPN(C. monogyna; syn: singleseed hawthorn)
found: Reader's digest encyc. of garden plants(C. monogyna; syn: common hawthorn, quick, may)
found: Phillips trees in Britain:p. 108 (common hawthorn; syn: C. monogyna)
found: Popular encyc. of plants(C. monogyna; syn: common hawthorn)
found: USDA cklist. of U.S. trees:p. 114 (C. monogyna; syn: oneseed hawthorn, English hawthorn, European hawthorn, singleseed hawthorn)