Gustaf Melander noin vuonna 1930.
<div class="fn value">
Unknown author<span style="display: none;">Unknown author</span></div>
circa 1930 <div style="display: none;">date QS:P571,+1930-00-00T00:00:00Z/9,P1480,Q5727902</div>
Ilmatieteen laitos: <a rel="nofollow" class="external free" href="https://helda.helsinki.fi/bitstream/handle/10138/144225/Keranen.pdf?sequence=1">https://helda.helsinki.fi/bitstream/handle/10138/144225/Keranen.pdf?sequence=1</a>, p. 130