Westwood; J. O. (John Obadiah); Metcalf Collection (North Carolina State University). NCRS; Tippmann Collection (North Kniga po trebovaniyu Saatavuus: Tilaustuote
Metcalf Collection (North Carolina State University). NCRS; Tippmann Collection (North Carolina State University). NCRS Kniga po trebovaniyu Saatavuus: Tilaustuote
Westwood; J. O. (John Obadiah); Metcalf Collection (North Carolina State University). NCRS; Tippmann Collection (North Kniga po trebovaniyu Saatavuus: Tilaustuote
Metcalf & Eddy, Inc., N/A; George Tchobanoglous; Franklin Burton; H. David Stensel McGraw-Hill Education (2003) Saatavuus: Painos loppu Kovakantinen kirja