Electrophilic aromatic substitution of napthalene
Essentially, both descriptions are identical. However, they use different phrasings.

What Carey and Sundberg mean when they say no allylic stabilisation is essentially that the cation itself is not in an allylic position; that there is no single (non-phenylic) double bond in &#x3b1;-position. To reach the allylic double bond in the &#x3b2;-attack case, you would need to resonate across at least part of the phenyl ring (meaning you’re already making use of benzylic stabilisation) while in the case of &#x3b1;-attack you have access to allylic resonance without interrupting the phenyl resonance.