A monograph of the Najades of Pennsylvania / by Arnold E. Ortmann.
Monograph of the Naiades of Pennsylvania
Ortmann, A. E. (Arnold Edward),
Published by the authority of the Board of Trustees of the Carnegie Institute,
AS36 .P7 vol.4, no 6; vol.8, no.1
Memoirs of the Carnegie Museum ; vol. 4, no.6, etc.
Publications of the Carnegie Museum, serial ; no. 64, 104.