Boolean function with characters in the function value, not 0 and 1

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I am currently studying the textbook Digital Design by Mano, and learned that the Boolean function can be expressed algebraically from a given truth table by forming a minterm for each combination of the variables that produces a 1 in the function and then taking the OR of all those terms.

If the following truth table was given,

x y|F          minterms
-----      ---------------
0 0|0        m_0   | x'y'
0 1|1        m_1   | x'y
1 0|0        m_2   | x y'
1 1|0        m_3   | x y

then the boolean function can be expressed as $$ F=m_1+m_3=x'y+xy. $$

So far the boolean function can be equal to either 1 or 0. What if there are characters in the function value, not 0 and 1?

x y|F*         
-----     
0 0|a        
0 1|b       
1 0|c    
1 1|d       

My initial guess for the boolean function $F^*$ was $$ F^*=m_0\cdot a + m_1\cdot b + m_2\cdot c + m_3\cdot d, $$ but I can't find any reference to support my assumption. Is my initial guess correct? And where do I find supporting references?