(R. P. )& Bitter, ?Abh. Naturwiss. Vereine Bremen 24: 442. 1919.?, 1919.

(R. P. )& Bitter, ?Abh. Naturwiss. Vereine Bremen 24: 348. 1919.?, 1919.

(R. P. )& Bitter and Bitter, (B. ), ?Abh. Naturwiss. Vereine Bremen 24: 443. 1919.?, 1919.

(R. P. )& Bitter, ?Abh. Naturwiss. Vereine Bremen 24: 453. 1919.?, 1919.