Wait, James R Circular of the Bureau of Standards No. 574: Amplitude and Phase Curves for Ground-wave Propagation in the Band 200 Cycles per Second to 500 Kilocycles; NBS Circular 574
![Wait, James R Circular of the Bureau of Standards No. 574: Amplitude and Phase Curves for Ground-wave Propagation in the Band 200 Cycles per Second to 500 Kilocycles; NBS Circular 574](https://r.kelkoo.com/resize.php?country=se&merchantId=100565793&categoryId=5101&trackingId=96964074&width=300&height=300&image=https%3A%2F%2Fm.media-amazon.com%2Fimages%2FI%2F41rgk0HY0DL._SL500_.jpg&sign=DnZDsWVoZpIJzk0WQz2b4r4k7YjqiQ4HxVRYPryaQms-)
Circular of the Bureau of Standards No. 574: Amplitude and Phase Curves for Ground-wave Propagation in the Band 200 Cycles per Second to 500 Kilocycles; NBS Circular 574