Language:
كتاب الأذان
10  
Call to Prayers (Adhaan)
(3)
Chapter: To pronounce the wording of Iqama once (in singles) except Qad-qamat-is-Salat
(3)
باب الإِقَامَةُ وَاحِدَةٌ، إِلاَّ قَوْلَهُ قَدْ قَامَتِ الصَّلاَةُ
Sahih al-Bukhari 607

Narrated Abu Qilaba:

Anas said, "Bilal was ordered to pronounce the wording of Adhan twice and of Iqama once only." The sub narrator Isma`il said, "I mentioned that to Aiyub and he added (to that), "Except Iqama (i.e. Qadqamat- is-salat which should be said twice).

حَدَّثَنَا عَلِيُّ بْنُ عَبْدِ اللَّهِ، حَدَّثَنَا إِسْمَاعِيلُ بْنُ إِبْرَاهِيمَ، حَدَّثَنَا خَالِدٌ، عَنْ أَبِي قِلاَبَةَ، عَنْ أَنَسٍ، قَالَ أُمِرَ بِلاَلٌ أَنْ يَشْفَعَ، الأَذَانَ، وَأَنْ يُوتِرَ الإِقَامَةَ‏.‏ قَالَ إِسْمَاعِيلُ فَذَكَرْتُ لأَيُّوبَ فَقَالَ إِلاَّ الإِقَامَةَ‏.‏
Reference : Sahih al-Bukhari 607
In-book reference : Book 10, Hadith 5
USC-MSA web (English) reference : Vol. 1, Book 11, Hadith 581
  (deprecated numbering scheme)