These are paid Amazon links*

A New Reference Grammar of Modern Spanish
USA: https://amzn.to/49fxW3s
CANADA: https://amzn.to/3QKB53X
UK: https://amzn.to/3suuAZP

Madrigal's Magic Key to Spanish:
USA: https://amzn.to/470b7iH
CANADA: No Link
UK: https://amzn.to/3u0aiIj

Breaking Out of Beginner’s Spanish
USA: https://amzn.to/3QOuupy
CANADA: https://amzn.to/47aO0Sm
UK: https://amzn.to/3u4tIM8

Spanish Verb Tenses
USA: https://amzn.to/3Snze6A
CANADA: https://amzn.to/3tTm86L
UK: https://amzn.to/3siiLWJ

Spanish Pronouns and Prepositions
USA: https://amzn.to/47j43NV
CANADA: https://amzn.to/3skg4E4
UK: https://amzn.to/3tZe4Bv

*As an Amazon Associate, I earn from qualifying purchases.