Shiva Purana
मुक्तिमार्गप्रवीणैश्च कर्तव्यं नियमादिति ॥ मुक्तेस्तु प्रापकं चैव चतुष्टयमुदाहृतम् ॥ १७ ॥
It should be done by those who are experts in the path of liberation by regulation The fourfold means of attaining liberation have been described.
english translation
muktimArgapravINaizca kartavyaM niyamAditi ॥ muktestu prApakaM caiva catuSTayamudAhRtam ॥ 17 ॥
hk transliteration by Sanscript