The Harriet Lane handbook :  a manual for pediatric house officers /  [The Harriet Lane Service at The Charlotte R. Bloomberg Children's Center of The Johns Hopkins Hospital ; editors, Helen Hughes, Lauren Kahl].   - Twenty-first edition. International edition.   - Philadelphia, PA :  Elsevier,  [2018]   - 1255 pages :  illustrations (some color) ;  19 cm   - Mobile medicine series .