 García Márquez researched a wide variety of historical documents , including Bolívar 's letters , 19th @-@ century newspapers , and Daniel Florencio O 'Leary 's 34 volumes of memoirs . He engaged the help of various experts , among them geographer Gladstone <unk> ; historian and fellow Colombian <unk> Gutiérrez <unk> , who had co @-@ written a book called Bolívar Día a Día with historian <unk> <unk> ; and astronomer Jorge <unk> — García Márquez used an inventory drawn up by <unk> to describe which nights Bolívar spent under a full moon . García Márquez also worked closely with Antonio Bolívar <unk> , a distant relative of Bolívar , during the extensive editing of the book . 
