Millard Meiss. French Painting in the Time of Jean de Berry. London, 1967, text vol., pp. 105–6; plate vol., fig. 530 (detail), as Giottesque, whereabouts unknown; says the seated postures of sacred figures, like those of Mary and Saint John the Evangelist in this work, reflect the religious values of early Trecento Italy which emphasized the humility of the saints; suggests that these postures derive from ancient Roman reliefs.
Miklós Boskovits in Richard Offner et al. "The Fourteenth Century: The Painters of the Miniaturist Tendency." A Critical and Historical Corpus of Florentine Painting. 9, section 3, new ed. Florence, 1984, pp. 339, 607, pl. CLXVIb, as location unknown; attributes it to Bernardo Daddi; calls it the fragmentary right shutter of a diptych and notes that the angels are largely a modern restoration.
Miklós Boskovits in Richard Offner et al. "The Fourteenth Century: The Works of Bernardo Daddi." A Critical and Historical Corpus of Florentine Painting. 3, section 3, new ed. Florence, 1989, pp. 88, 391.