Ah, page 1961. This is a notable year in Norwegian football: It was the last year when the top flight season ended in the spring, and the last year when the league consisted of a Western and an Eastern conference. Until 1961, the league champion would be decided by a single final match between the winners of each conference.
Coincidentally (or maybe not), 1961 was also the year of Fredrikstad FK's 9th and hitherto last league title. 1960-61 was also the season they made their only notable international achievement, by eliminating Ajax from the first round of the European Cup.
The transition from autumn-spring to spring-autumn league football was done by playing an extended season starting in the autumn of 1961 and finishing in the autumn of 1962 (the so-called Marathon Series). Since then, the Norwegian football season has started in the spring (typically April) and finished late October (early November)