(en) Bruce Spizer, « An Apple a Day: Mary Hopkin – Post Card », sur Beatlesnews.com, Adam Forrest, (consulté le ) : « Mary Hopkin's debut single paired "Those Were The Days," a Lithuanian folk song adapted by American Gene Raskin »
(it) « I singoli più venduti del 1968 », sur HitParadeItalia.it, Creative Commons (consulté le ) 73. Those were the days (Quelli erano giorni) - Mary Hopkin [#15]