I've noticed that 'sentences' without a main verb are more common in formal writing in Norwegian than in English. Maybe they're not considered incorrect. Here's an example from a government document: 'Fellesnevneren for disse tilsynssakene er at de gjelder alvorlig syke pasienter og at feilene som er begått har hatt alvorlige konsekvenser for pasientene. Videre at sakene ofte involverer annet helsepersonell og andre helsetjenestetilbud.' Now my British brain (despite umpteen years in Norway) would want to write 'Dessuten involverer sakene ofte...' instead of 'Videre at...' because then it would be what in British eyes is a 'proper sentence'. There are many others I've seen, apart from 'Videre at...', for example starting a new 'sentence' with 'Noe som...' instead of just adding a comma to the previous sentence '...pasienter, noe som...' Perhaps Norwegians don't consider such things to be mistakes, or at least are more tolerant of them than a British teacher or proof-reader would be (?)