First European physics olympiad - short and challenging problemsHeidelberg, Mihkel; Vigh, Mate; Kalda, JaanEuropean journal of physics2018 / 16 p.: ill https://doi.org/10.1088/1361-6404/aab59f Journal metrics at Scopus Article at Scopus Journal metrics at WOS Article at WOS IPhO 2012: how magnets curve the waterKalda, Jaan; Kikas, Jaak; Heidelberg, M.; Ainsaar, Ain; Lõhmus, RünnoEuropean journal of physics2013 / p. S35-S48 : ill The 'Physics Cup' : interesting problems are difficultKalda, JaanEuropean journal of physics2013 / p. S3-S-14 : ill