ŽIVČÁK, Marek et al. Screening for drought tolerance in lettuce using chlorophyll fluorescence imaging: limits and possibilities. In Photosynthesis and hydrogen energy research for sustainability. 1st ed. 247 s. ISBN 978-93-5288-261-8. Photosynthesis and hydrogen energy research for sustainability. Hyderabad : University of Hyderabad, 2017, s. 196. Available on Internet:<https://prs.science/wp-content/uploads/2017/10/Photosynthesis-Research-for-Sustainability-2017.pdf>