Khaleghi Gazik, S., Saffari, V. R., & Daneshvar, S. "Effect of different levels of biochar, hydrochar and salicylic acid on the growth of Calendula officinalis L.", Iranian Journal of Horticultural Science, 53, 3, 2022, 553-566. doi: 10.22059/ijhs.2021.328082.1958