I know that the Knapsack problem is weakly NP-complete. I also notice that on Wikipedia:
"A problem is said to be strongly NP-hard if a strongly NP-complete problem has a polynomial reduction to it [...]"
The way I prove the NP-hardness is by a reduction chain: SAT $\leq$ 3SAT $\leq$ Tripartite Matching $\leq$ Exact cover by 3-sets $\leq$ Subset sum $\leq$ Knapsack.
Does it mean all these problems are weakly NP-complete? Because it seems that according to Wikipedia if one of them is strongly NP-complete, Knapsack will be strongly NP-complete.