Não informado. Science in agriculture. Pennsylvania Agricultural Experiment Station.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Science in Agriculture. University Park, Pa: Pennsylvania Agricultural Experiment Station.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Science in Agriculture. Pennsylvania Agricultural Experiment Station.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.