Shiva Purana
सोमवारादिवारेषु तत्तद्वारगुणं फलम् । अन्नदानस्य विज्ञेयं भूर्लोके परजन्मनि 1-15-३० ।
If he gives the same on Monday or any other day, he attains the benefit as stipulated for that day. The benefit of food-gifts is secured in this world itself either in this birth or in the next.
english translation
somavArAdivAreSu tattadvAraguNaM phalam । annadAnasya vijJeyaM bhUrloke parajanmani 1-15-30 ।
hk transliteration by Sanscript