Those studies appear to no longer exist, the web links to the analysis' are deadends.
Sorry about that.
There are various ways I see to convert the voting into %s, in the case of your study "Selke shares."
First, you can use the maximum points one player can get as the standard. So if there are 60 voters and 5 points for 1st, the max would be 300. Then convert each player's voting points into a % share for that season.
Second, you can use total available points (or a constant % of such) as the standard. So, if it's 5-3-1 for 1st-2nd-3rd, and there are 60 voters, then the total points available would be 540. Then convert each player's voting points into a % share for that season.
Another way is to use the total points of the first place finisher as the standard. This has the disadvantage of varying from season to season, depending on the % of max points the first place finisher receives.
There are a couple of factors to consider for either/both method(s). If the voting point system changes (more places and/or different number of points), this will affect each system differently and affect various players (high finishers, low finishers) differently. You aren't bound to the actual point system used and could assign different values to the 1st, 2nd, etc. votes than those actually assigned by the award. Also, using total points available and/or possibly adjusting by a constant proportional to the total points avaiable on each ballot will affect various players differently. On a 5-3-1 ballot, the most a player can get is 5/9 or 55.6% of the total points. On a 3-2-1 ballot, the most a player can get is 3/6 or 50% of the total points.
Just realize that there is no simple solution, but that whatever method you use will affect the results. You might tinker with various ways and see which way(s) seem best.