Yarligan Uysal, Selma, and Emre Yildirim. “Extraction and Characterization of Pectin from Red Hawthorn (Crataegus spp.) Using Citric Acid and Lemon Juice”. Asian Journal of Chemistry, vol. 26, no. 19, Sept. 2014, pp. 6674-8, doi:10.14233/ajchem.2014.17590.