The Protozoa - Calkins, Gary N. (Gary Nathan), 1869 -1943 (The Macmillan company, 1901)

The Protozoa, by Gary N. Calkins - Calkins, Gary N. (Gary Nathan), 1869 -1943 (Macmillan, 1901)

The Protozoa - Calkins, Gary N. (Gary Nathan), 1869 -1943 (Macmillan, 1901)

Protozoa in biological research - Calkins, Gary N. (Gary Nathan), 1869 -1943 (Columbia University Press, 1941)

Protozoa - Schwager, Conrad. (C.F. Winter, 1880)

Protozoa - Schwager, Conrad. (C.F. Winter, 1883)

Protozoa - Schwager, Conrad. (C.F. Winter, 1887)

Protozoölogy - Calkins, Gary N. (Gary Nathan), 1869 -1943 (Lea & Febiger, 1909)

Protozoology - Kudo, Richard R. (Richard Roksabro), 1886 -1967 (C. C. Thomas, 1954)

Protozoology - Hall, Richard P. (Richard Pinkham), 1900 -1969 (Prentice-Hall, 1953)