Ogorzałek, Marta, and Tomasz Wasilewski. “The Application of Hydrophobic Calendula Officinalis Flower Extract in the Manufacture of Handwashing Liquid Laundry Detergents”. Studia Oeconomica Posnaniensia, vol. 5, no. 7, July 2017, pp. 45-58, https://doi.org/10.18559/SOEP.2017.7.4.