كتاب الذكر والدعاء والتوبة والاستغفار
48  
The Book Pertaining to the Remembrance of Allah, Supplication, Repentance and Seeking Forgiveness
(13)
Chapter: It Is Recommend To Lower One's Voice When Saying Remembrance, Except In The Cases Where It Is Commanded To Raise The Voice Such As The Talbiyah Etc. It Is Recommend To Say A Great Deal, "There Is No Power And No Strength Except With Allah"
(13)
باب اسْتِحْبَابِ خَفْضِ الصَّوْتِ بِالذِّكْرِ
Sahih Muslim 2704 b

This hadith has been narrated on the authority of 'Asim with the same chain of transmitters.

حَدَّثَنَا ابْنُ نُمَيْرٍ، وَإِسْحَاقُ بْنُ إِبْرَاهِيمَ، وَأَبُو سَعِيدٍ الأَشَجُّ جَمِيعًا عَنْ حَفْصِ بْنِ، غِيَاثٍ عَنْ عَاصِمٍ، بِهَذَا الإِسْنَادِ نَحْوَهُ ‏.‏
Reference : Sahih Muslim 2704b
In-book reference : Book 48, Hadith 57
USC-MSA web (English) reference : Book 35, Hadith 6527
  (deprecated numbering scheme)