In 1950 Fellini co-produced and co-directed with Alberto Lattuada Variety Lights (Luci del varieta), his first feature film. A backstage comedy set among the world of small-time travelling performers, it featured Giulietta Masina and Lattuada's wife, Carla del Poggio. Its release to poor reviews and limited distribution proved disastrous for all concerned. The production company went bankrupt, leaving both Fellini and Lattuada with debts to pay for over a decade. In February 1950, Paisa received an Oscar nomination for the screenplay by Rossellini, Sergio Amidei, and Fellini. After travelling to Paris for a script conference with Rossellini on Europa '51, Fellini began production on The White Sheik in September 1951, his first solo-directed feature. Starring Alberto Sordi in the title role, the film is a revised version of a treatment first written by Michelangelo Antonioni in 1949 and based on the fotoromanzi, the photographed cartoon strip romances popular in Italy at the time. Producer Carlo Ponti commissioned Fellini and Tullio Pinelli to write the script but Antonioni rejected the story they developed. With Ennio Flaiano, they re-worked the material into a light-hearted satire about newlywed couple Ivan and Wanda Cavalli (Leopoldo Trieste, Brunella Bovo) in Rome to visit the Pope. Ivan's prissy mask of respectability is soon demolished by his wife's obsession with the White Sheik. Highlighting the music of Nino Rota, the film was selected at Cannes (among the films in competition was Orson Welles's Othello) and then retracted. Screened at the 13th Venice International Film Festival, it was razzed by critics in "the atmosphere of a soccer match". One reviewer declared that Fellini had "not the slightest aptitude for cinema direction". In 1953, I Vitelloni found favour with the critics and public. Winning the Silver Lion Award in Venice, it secured Fellini his first international distributor.

Answer this question "did he work alone in production" by extracting the answer from the text above.
Carlo Ponti commissioned Fellini and Tullio Pinelli to write the script