Vintage 70s 80s Ace Tempo Classics box set - Heidi, Black Beauty, Swiss family

Box: Acceptable - Books: Very Good This boxed set is from 1980 I believe. The books vary in date by ISBN, with two being published in 1980, and two in the 70s. Box is in acceptable condition, with cardboard still firm and edges sharp. There is wear to the bottom, pictured. Books inside are in good - very good condition, with just one having a name written in pen in front cover. All bindings are tight with no bent pages, and it seems they haven't been read. Very light wear to covers. Heidi, Black Beauty, and The Swiss Family Robinson all have a few illustrations. 1. The Swiss Family Robinson - ISBN: 0448168901 2. Rebecca of Sunnybrook Farm - ISBN: 0448172380 3. HEidi - ISBN: 0448173395 4. Black Beauty - ISBN: 0448170639