Manusmriti
तासामाद्याश्चतस्रस्तु निन्दितैकादशी च या । त्रयोदशी च शेषास्तु प्रशस्ता दशरात्रयः ॥ ४७ ॥
But among these the first four, the eleventh and the thirteenth are (declared to be) forbidden; the remaining nights are recommended.
english translation
tAsAmAdyAzcatasrastu ninditaikAdazI ca yA । trayodazI ca zeSAstu prazastA dazarAtrayaH ॥ 47 ॥
hk transliteration by Sanscript