On non-marine shells from Northeastern Brazil and Peru.

v.37:no.10(1955)

Notes on a collection of birds from northeastern Colombia.

v.44:no.4(1961)

Birds of northeastern Peru / Melvin A. Traylor.

v.35:no.5(1958)

Fresh-water limestone from the Torola Valley, northeastern El Salvador / Sharat Kumar Roy -- and Robert Kriss Wyant --.

v.10:no.16(1953)

Diplocaulus : a study in growth and variation / Everett Claire Olson --

v.11:no.2(1951)