Hammer, Paul. "Greenhouse studies on the effect of chemical growth retardants on shoot growth of Chrysanthemum morifolium Ramat. and Euphorbia pulcherrima Willd /." Doctoral dissertation, Ohio State University, 1974. http://rave.ohiolink.edu/etdc/view?acc_num=osu1486980617307185Chicago Manual of Style (17th edition)