By Heike Kamerlingh Onnes. KNAW Proceedings 17 I, 278–283; Leiden Communication 140c. Communicated 30 May 1914; digitized 2010. English translator uncredited.
The Liquefaction of Helium by Heike Kamerlingh Onnes Created 2026-10-18 Updated 2026-11-05
Proceedings 11:168–185; English translator uncredited; imprint 1909.