Carnegie Institution of Washington publication.

no. 173, pt. 1 (1913)

Carnegie Institution of Washington publication.

no. 173, pt. 2 (1913)

Carnegie Institution of Washington publication.

no. 179 (1913)

Carnegie Institution of Washington publication.

no. 188 (1913)

Carnegie Institution of Washington publication.

no. 181 (1913)

Carnegie Institution of Washington publication.

no. 177 (1913)

The Nature-study review : devoted to all phases of nature-study in elementary schools.

v. 9 (1913)

The Popular science monthly.

v. 82 (1913)

Proceedings of the Academy of Natural Sciences of Philadelphia.

Index 1812-1912 (1913)

The Nautilus.

v.26 (1912-1913)

The Nautilus.

v.27 (1913-1914)

Biologisches Zentralblatt.

bd. 33 (1913)