Kurkela, Rakel, Anita Ellala, and Lasse Vanhanen. “Kahdella Eri Lannoitustasolla Viljeltyjen Perunalajikkeiden Laatu Ruokaperunana”. Agricultural and Food Science 43, no. 4 (December 1, 1971): 231–239. Accessed January 7, 2025. https://journal.fi/afs/article/view/71802.