3 1970s Nancy Drew Mystery Stories Hardcovers 47 48 49

3 1970s Nancy Drew Mystery Stories Hardcovers 47 48 49. This lot includes:
(1) 47 The Mysterious Mannequin. This was published in the year 1970.
(1) 48 The Crooked Banister. This was published in the year 1971.
(1) 49 The Secret Of Mirror Bay. This was published in the year 1972. Each book is approx 5" x 3/4" x 7 1/2" and the total weight is 1.82lb. The books were published by Grosset & Dunlap and were written under the pseudonym of Carolyn Keene. The covers have shelf wear and there is some handwriting on the pages.