Flora of Guatemala / Paul C. Standley and Louis O. Williams.

v.24:pt.7:no.1(1961)

Tropical American plants, X / Louis O. Williams.

v.32:no.4(1968)

Tropical American plants, XI / Louis O. Williams.

v.32:no.12(1970)

Flora of Guatemala / Dorothy L. Nash, Louis O. Williams ; genera contributed by Kenneth M. Becker ... [et al.].

v.24:pt.12(1976)

Flora of Guatemala / Paul C. Standley and Louis O. Williams.

v.24:pt.7:no.4(1963)

Tropical American plants, VII / Louis O. Williams.

v.31:no.6(1965)

Flora of Guatemala / Paul C. Standley and Louis O. Williams.

v.24:pt.7:no.2(1962)

Tropical American plants, VI / Louis O. Williams.

v.31:no.2(1964)

Flora of Guatemala / by Paul C. Standley and Louis O. Williams.

v.24:pt.11:no.1-3(1975)

An overlooked genus of the Scrophulariaceae / Louis O. Williams.

v.32:no.14(1970)

Tropical American plants, IX / Louis O. Williams.

v.31:no.18(1968)

Tropical American plants, V / Louis O. Williams.

v.29:no.10(1963)

Flora of Guatemala / Paul C. Standley and Louis O. Williams.

v.24:pt.9:no.1-2(1970)

Tropical American plants, VIII / Louis O. Williams.

v.31:no.10(1967)

Tropical American plants, III / Louis O. Williams.

v.29:no.7(1962)