Information circulars. 8417. Helium symposia proceedings in 1968 — A hundred years of helium. Helium Applications Symposium, Washington, D.C. Oct. 23-24, 1968 [and] Helium Centennial Symposium, Atlantic City, N.J., Sept. 11, 1968 [papers, with lists of references]; compiled by Harold W. Lipper.