On the phenolic acids of vegetables part 2 hydroxy cinnamic acids and hydroxy benzoic acids of fruit and seed vegetables Schmidtlein, H.; Herrmann, K. Zeitschrift fuer Lebensmittel-Untersuchung und -Forschung 159(4): 213-218 1975 https://eurekamag.com/research/027/081/027081184.php