electrical discharge diagrams from Meyers Konversationslexikon 6th edition, 1902 - 1920 (source) / trachyline species from phylogenetics of trachylina (cnidaria: hydrozoa) with new insights on the evolution of some problematical taxa, 2008 (source) / analogue computer prototype by bernd ulmann (tibor florestan pluto) / svenska lafvarnas färghistoria (color history of swedish lichens), ~1805-1809 (biodiversity heritage library)