Which specific international leagues did Nielsen compete in throughout his career and how did his performance compare to Denmark?
Based on the article provided, there are no specific names of foreign leagues or individual countries mentioned. The text only notes that his career involved traversing different leagues and various international borders, but it does not list the exact locations or specific competitions he participated in outside of Denmark.
Because the text does not identify these foreign leagues, it is also not possible to determine how his performance level changed or whether he maintained his level of play while competing abroad. The article focuses on the movement across borders rather than providing a detailed breakdown of his statistical performance or the specific names of the international clubs he joined.
