You don't need to give credit. You can also find them here! https://symbl.cc/en/collections/roman-numerals/ It includes a combined 2, 3, 4, 6, 7, 8, 9, 11, and 12 as well! It also includes the ancient versions of 6, 50, and 1000! It even includes numbers above 1000 up to 100000! Have fun, feel free to remix!
You don't need to copy the letters I, V, X, L, C, D, M! You already have them on your keyboard! C2A