Volume 7, Issue 4 Friedrich Philipp Indefinite Sturm-Liouville operators with periodic coefficients Downloads Abstract PDF Full article PDF DOI { copied = true; setTimeout(() => copied = false, 2000) })" :aria-label="copied ? 'DOI copied' : 'Copy DOI'" :title="copied ? 'Copied' : 'Copy DOI'" > Find all available articles from these authors Friedrich Philipp Find more articles with the same keywords Sturm-Liouville operator periodic coefficients indefinite weight Find more articles with the same subject classes 34B09 34B24 34L10 47B50 47E05