CREATE TABLE paperdataset (paperid INT, datasetid INT)
CREATE TABLE journal (journalid INT, journalname VARCHAR)
CREATE TABLE paper (paperid INT, title VARCHAR, venueid INT, year INT, numciting INT, numcitedby INT, journalid INT)
CREATE TABLE paperfield (fieldid INT, paperid INT)
CREATE TABLE author (authorid INT, authorname VARCHAR)
CREATE TABLE dataset (datasetid INT, datasetname VARCHAR)
CREATE TABLE cite (citingpaperid INT, citedpaperid INT)
CREATE TABLE field (fieldid INT)
CREATE TABLE paperkeyphrase (paperid INT, keyphraseid INT)
CREATE TABLE venue (venueid INT, venuename VARCHAR)
CREATE TABLE keyphrase (keyphraseid INT, keyphrasename VARCHAR)
CREATE TABLE writes (paperid INT, authorid INT)

Papers by Frank Keller and Mirella Lapata
SELECT DISTINCT WRITES_0.paperid FROM author AS AUTHOR_0, author AS AUTHOR_1, writes AS WRITES_0, writes AS WRITES_1 WHERE AUTHOR_0.authorname = 'Frank Keller' AND AUTHOR_1.authorname = 'Mirella Lapata' AND WRITES_0.authorid = AUTHOR_0.authorid AND WRITES_1.authorid = AUTHOR_1.authorid AND WRITES_1.paperid = WRITES_0.paperid
SELECT DISTINCT "WRITES_0"."paperid" FROM "author" AS "AUTHOR_0" JOIN "writes" AS "WRITES_0" ON "AUTHOR_0"."authorid" = "WRITES_0"."authorid" JOIN "writes" AS "WRITES_1" ON "WRITES_0"."paperid" = "WRITES_1"."paperid" JOIN "author" AS "AUTHOR_1" ON "AUTHOR_1"."authorid" = "WRITES_1"."authorid" AND "AUTHOR_1"."authorname" = 'Mirella Lapata' WHERE "AUTHOR_0"."authorname" = 'Frank Keller'