sentences:  He and Hirschfeld co-authored several articles on sexology.In 1913, Burchard published his books "Zur Psychologie der Selbstbezichtigung" and "Der sexuelle Infantilismus", and in 1914 he published his "Lexikon des gesamten Sexuallebens".Burchard also wrote lyric poems for the gay periodicals "Der Eigene" and "Jahrbuch für sexuelle Zwischenstufen", including the poem "Vivat Fridericus".