Petrulionis. Thoreau in His Own Time. University of Iowa Press.
Citazione stile Chigago Style (17a edizione)Petrulionis. Thoreau in His Own Time. University of Iowa Press.
Citatione MLA (9a ed.)Petrulionis. Thoreau in His Own Time. University of Iowa Press.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.