1. Howard, H. W.: The fertility of amphidiploids from the crossRaphanus sativus x Brassica oleracea. J. Genet.36, 239–273.
2. Kihara, H., andJ. Nisiyama: Possibility of crossing over between semihomologous chromosomes from two different genoms. Cytologia. Fujii Jubil. Vol.1937, 654 bis 666.
3. Kostoff, D.: The occurence of crossing over inNicotiana species hybrids. Curr. Sc.2, 370–373 (1934).
4. Kostoff, D.: Conjugation between morphologically different chromosomes inNicotiana species hybrids. C. r. Acad. Sci. USSR1, Nr. 7/8, 558–560 (1935).
5. Kostoff, D.: Formation of a quadrivalent group in a hybrid betweenTriticum vulgare and aTriticum vulgare extracted derivative Curr. Sci.5, 537 (1937a).