Non-formal compact manifolds with small Betti numbers
  We show that, for any $k\geq 1$, there exist non-formal compact orientable $(k-1)$-connected $n$-manifolds with $k$-th Betti number $b_k=b\geq 0$ if and only if $n\geq \max \{4k-1, 4k+3-2b\}$. 
Marisa Fernandez and Vicente Mu\~noz