Letters that make source materials
s, a, o, e, l, c, m, r, t, i, u are letters that make 'source materials'
Words within source materials
ER, source, rial, MA, MAT, te, ma, mater, sou, at, ALS, RI, mA, mat, material, sour, CE, so, mate, Ur, AL, IA, Ate, Al, At, Ce, Er, Te are words within 'source materials'