Published in Bulletin of the British Ornithologists' Club, in 1931, in volume 51, pages 59

Published in Bulletin of The British Ornithologists' Club, in 1931, in volume 51, pages 80-81

Published in Bulletin of the British Ornithologists' Club, in 1931, in volume 51, pages 81

Published in Bulletin of the British Ornithologists' Club, in 1931, in volume 51, pages 109-112