This is the sort of thing you can Google, because it is extremely common advice. A few of the top hits: https://www.fonts.com/content/learning/fontology/level-

This is the sort of thing you can Google, because it is extremely common advice. A few of the top hits: https://www.fonts.com/content/learning/fontology/level-2/text-typography/length-column-width https://www.fonts.com/content/learning/fontology/level-2/tex... https://pimpmytype.com/line-length-line-height/ https://pimpmytype.com/line-length-line-height/ https://material.io/design/typography/understanding-typography.html#readability https://material.io/design/typography/understanding-typograp... (see under Line Length) I don't have any studies at hand, but I think it's been pretty well established.