Which late Igor Stravinsky works use serial techniques?

Following his Neoclassical period, Igor Stravinsky entered a phase of serial composition, adopting the 12-tone techniques associated with composers like Arnold Schoenberg and Anton von Webern.1

His late works utilizing these serial techniques include:

• Experimental works: The Cantata, the Septet, and In Memoriam Dylan Thomas.1
• Hybrid masterpieces: The ballet Agon (1957) and the choral work Canticum Sacrum (1955), which are only intermittently serial.1
• Strict serial works: The choral work Threni (1958), which applies a strict 12-tone method to chantlike material.1
• Refined serial works: Movements for piano and orchestra (1959) and the orchestral Variations (1964), which pursue arcane serial techniques.1
• Final major work: Requiem Canticles (1966), which adapts modern serial techniques to his personal imaginative vision.1

These serial compositions are generally more brief and dense than his earlier tonal works.1