            <math overflow="scroll">

                            <msub><mi mathvariant="italic">b</mi>
                            <mn>2</mn>
                            </msub>
                        </math>,
                        <math overflow="scroll">

                            <msub><mi mathvariant="italic">b</mi>
                            <mn>1</mn>
                            </msub>
                        </math>,
                        <math overflow="scroll">

                          