1. De Mairan, Observation botanique. Histoire
de l‘Academie Royale
des Sciences, Paris 35 (1729).
2. Duhamel de Monceau, La Physique des Arbres, 2, 158–159 (1758).
3. J. G. Zinn, Von dem Schafe der Pflanzen. Hamburgischen Magazin, 22, 40–50 (1759).
4. W. W. Garner and H. A. Allard, Effect of the relative length of day and night and other factors of the environment on growth and reproduction in plants. J. Agr. Res., 18, 553–606 (1920).
5. W. W. Garner and H. A. Allard, Further studies in photoperiodism, the response of plants to relative length of day and night. J. Agr. Res., 23, 871–920 (1923).