Some context: George Michael Cohan (July 3, 1878 - November 5, 1942), known professionally as George M. Cohan, was an American entertainer, playwright, composer, lyricist, actor, singer, dancer and producer. Cohan began his career as a child, performing with his parents and sister in a vaudeville act known as "The Four Cohans." Beginning with Little Johnny Jones in 1904, he wrote, composed, produced, and appeared in more than three dozen Broadway musicals. Cohan published more than 300 songs during his lifetime, including the standards "Over There", "Give My Regards to Broadway", "The Yankee Doodle Boy" and "You're a Grand Old Flag".
Cohan appeared in 1930 in a revival of his tribute to vaudeville and his father, The Song and Dance Man. In 1932, Cohan starred in a dual role as a cold, corrupt politician and his charming, idealistic campaign double in the Hollywood musical film The Phantom President. The film co-starred Claudette Colbert and Jimmy Durante, with songs by Rodgers and Hart, and was released by Paramount Pictures. He appeared in some earlier silent films but he disliked Hollywood production methods and only made one other sound film, Gambling (1934), based on his own 1929 play and shot in New York City. A critic called Gambling a "stodgy adaptation of a definitely dated play directed in obsolete theatrical technique." It is considered a lost film. Cohan earned acclaim as a serious actor in Eugene O'Neill's only comedy, Ah, Wilderness! (1933), and in the role of a song-and-dance President Franklin D. Roosevelt in Rodgers and Hart's musical I'd Rather Be Right (1937). The same year, he reunited with Harris to produce a play called Fulton of Oak Falls, starring Cohan. His final play, The Return of the Vagabond (1940), featured a young Celeste Holm in the cast. In 1940, Judy Garland played the title role in a film version of his 1922 musical Little Nellie Kelly. Cohan's mystery play Seven Keys to Baldpate was first filmed in 1916 and has been remade seven times, most recently as House of Long Shadows (1983), starring Vincent Price. In 1942, a musical biopic of Cohan, Yankee Doodle Dandy, was released, and James Cagney's performance in the title role earned the Best Actor Academy Award. The film was privately screened for Cohan as he battled the last stages of abdominal cancer; Cohan's comment on Cagney's performance was, "My God, what an act to follow!" Cohan's 1920 play The Meanest Man in the World was filmed in 1943 with Jack Benny.
What happened in his later career
A: Cohan appeared in 1930 in a revival of his tribute to vaudeville and his father, The Song and Dance Man.

Some context: Robert Dennis Crumb (; born August 30, 1943) is an American cartoonist and musician who often signs his work R. Crumb. His work displays a nostalgia for American folk culture of the late 19th and early 20th centuries, and satire of contemporary American culture. Crumb is a prolific artist and contributed to many of the seminal works of the underground comix movement in the 1960s, including being a founder of the first successful underground comix publication, Zap Comix, contributing to all 16 issues. He was additionally contributing to the East Village Other and many other publications, including a variety of one-off and anthology comics.
In January 1967 Crumb came across two friends in a bar who were about to leave for San Francisco; Crumb was interested in the work of San Francisco-based psychedelic poster artists, and on a whim asked if he could join them. There, he contributed upbeat LSD-inspired countercultural work to underground newspapers. The work was popular, and Crumb was flooded with requests, including to illustrate a full issue of Philadelphia's Yarrowstalks. Independent publisher Don Donahue invited Crumb to make a comic book; Crumb drew up two issues of Zap Comix, and Donahue published the first in February 1968 under the publisher name Apex Novelties. Crumb had difficulty at first finding retailers who would stock it, and at first his wife took to selling the first run herself out of a baby carriage. Crumb met cartoonist S. Clay Wilson, an art school graduate who saw himself as a rebel against middle-class American values and whose comics were violent and grotesque. Wilson's attitude inspired Crumb to give up the idea of the cartoonist-as-entertainer and to focus on comics as open, uncensored self-expression; in particular, his work soon became sexually explicit, as in the pornographic Snatch he and Wilson produced late in 1968. The second issue of Zap appeared in June with contributions from Wilson and poster artists Victor Moscoso and Rick Griffin. In December, Donahue published the still-unreleased issue as #0 and a new third issue with Gilbert Shelton joining the roster of regulars. Zap was financially successful, and developed a market for underground comix. Crumb was a prolific cartoonist in the late 1960s and early 1970s; at his peak point of output he produced 320 pages over two years. He produced much of his best-known work then, including his Keep on Truckin' strip, and strips featuring characters such as the bohemian Fritz the Cat, spiritual guru Mr. Natural, and oversexed African-American stereotype Angelfood McSpade. During this period, he launched a series of solo titles, including Despair, Uneeda (both published by Print Mint in 1969), Big Ass Comics, R. Crumb's Comics and Stories, Motor City Comics (all published by Rip Off Press in 1969), Home Grown Funnies (Kitchen Sink Press, 1971) and Hytone Comix (Apex Novelties, 1971), in addition to founding the pornographic anthologies Jiz and Snatch (both Apex Novelties, 1969).
what were these best known works?
A:
Home Grown Funnies (Kitchen Sink Press, 1971) and Hytone Comix (Apex Novelties, 1971), in addition to founding the pornographic anthologies Jiz and Snatch (both Apex Novelties, 1969).