On Extensions of supersingular representations of ${\rm   SL}_2(\mathbb{Q}_p)$
  In this note for $p>5$ we calculate the dimensions of ${\rm Ext}^1_{{\rm SL}_2(\mathbb{Q}_p)}(\tau, \sigma)$ for any two irreducible supersingular representations $\tau$ and $\sigma$ of ${\rm SL}_2(\mathbb{Q}_p)$. 
Santosh Nadimpalli
math.RT math.NT