ヘルシンキ・フィルハーモニー管弦楽団
Berglund's source-critical research on the Sibelius Seventh Symphony began in 1957, when he conducted the Seventh with the Helsinki Philharmonic Orchestra, and noticed that they were playing from parts that Sibelius had corrected. He saw that the printed parts had numerous errors. His subsequent research led to the publication of a new edition of the symphony by Hansen in 1980.