Guthnick, Paul, 1879- ,and Richard Prager, 1883- **E.5140.20.1 Photoelektrische Untersuchungen an spektroskopischen Doppel- sternen und an Planeten. — Berlin. Diimmler. 1914. viii, 68 pp. Plates. Plans. Charts. [Koenigliche Sternwarte, Berlin-Babelsberg. Verdffentlichun- gen. Band 1, Heft 1.] 30% cm., in 4s.
This card was printed at the Boston SD Public Library, April 28, 1915
K4786 — S.r.c. — Photo-electricity. — Stars. Double. — Planets. — Jt. auth.