Molecular basis of the biological clock: induction of carotenoids may be related to the phase shifting in the photosynthetic unicell gonyaulax polyedra - Speranca, M A; Marinelli, D; Colepicolo, Pio; Di Mascio, Paolo (Reuniao Anual da Sociedade Brasileira de Bioquimica e Biologia Molecular, 1993)