The NFL and ALS: Before Dwight Clark, three 49ers were victims
Do football injuries cause ALS? We explain the evidence
Reaction to the death of 49ers great Dwight Clark
Dwight Clark Cause of Death: How Did The 49ers Legend Die?
Golden Nuggets: Dwight Clark passes after ALS battle - Niners Nation
Former 49ers great Dwight Clark says he has ALS, suspects football caused it
49ers' Dwight Clark tragedy: Can football cause ALS? – Santa Cruz Sentinel
At least a dozen NFL players have suffered from ALS
Dwight Clark Cause of Death: San Francisco 49ers Great Known for 'the Catch' Dead at 61