Clasificación de la Biblioteca del CongresoS942.M27

1930s(5) activism(8) Africa(12) agriculture(16) American(11) American West(14) animals(20) astrology(7) biography(37) biology(14) birds(9) botany(5) California(9) career(6) chemistry(11) children(8) children's(6) conservation(209) development(10) diary(7) earth(14) ecology(139) economics(11) ecosystems(6) education(9) endangered species(5) environment(201) environmental(29) environmental policy(7) environmental studies(11) environmentalism(68) essay(6) geography(20) geology(16) government(8) Great Depression(16) green(12) history(85) humor(10) Iowa(8) journalism(8) literature(8) management(10) mining(5) Minnesota(5) music(5) National Parks(18) natural resources(31) nature(165) nature writing(11) New Deal(23) New Mexico(6) outdoors(5) photographs(10) photography(10) picture book(5) policy(5) politics(25) pollution(16) queer(6) reference(13) romance(11) science(100) sustainability(17) trans(7) travel(13) trees(9) us(5) usa(25) wilderness(8) wildlife(23)