The second moment of Maass form symmetric square L-functions at the central point

Recently R.Khan and M.Young proved a mean Lindel\"{o}f estimate on the second moment of central values of Maass form symmetric-square L-function on the interval T<|tⱼ|<T+T1/5+ε, where tⱼ is a spectral parameter of the Maass form. We provide another proof of this result.