Shiva Purana
सगर्भादपि साहस्रं सध्यानो जप उच्यते ॥ एषु पञ्चविधेष्वेकः कर्तव्यः शक्तितो जपः ॥ ३३ ॥
The Sadhyāna Japa is a thousand times better than the Sagarbha Japa. One of the five types of Japas shall be performed upto the extent of one’s ability.
english translation
sagarbhAdapi sAhasraM sadhyAno japa ucyate ॥ eSu paJcavidheSvekaH kartavyaH zaktito japaH ॥ 33 ॥
hk transliteration by Sanscript